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SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 13D Under the Securities Exchange Act of 1934 (Amendment No. 13)* CABOT CORPORATION (Name of Issuer) COMMON STOCK, PAR VALUE $1.00 PER SHARE (Title of Class of Securities) 127055101 (CUSIP Number) SPO Advisory Corp. 591 Redwood Highway, Suite 3215 Mill Valley, California 94941 (415) 383-6600 with a copy to: Alison S. Ressler Sullivan & Cromwell LLP 1888 Century Park East Los Angeles, California 90067-1725 (310) 712-6600 (Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications) August 19, 2009 (Date of Event which Requires Filing of This Statement) If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this Schedule because of Rule 13d-1(e), 13d-1(f) or 13d-1(g), check the following box [_]. Note. Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits. See Rule 13d-7 for other parties to whom copies are to be sent. *The remainder of this cover page shall be filled out for a reporting person's initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter disclosures provided in a prior cover page. The information required on the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

Page 2 of 41 pages CUSIP No. 127055101 - -------------------------------------------------------------------------------- 1. NAME OF REPORTING PERSON SPO Partners II, L.P. - -------------------------------------------------------------------------------- 2. CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP: (a) [_] (b) [X] - -------------------------------------------------------------------------------- 3. SEC Use Only - -------------------------------------------------------------------------------- 4. SOURCE OF FUNDS WC - -------------------------------------------------------------------------------- 5. CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e) [_] - -------------------------------------------------------------------------------- 6. CITIZENSHIP OR PLACE OF ORGANIZATION Delaware - -------------------------------------------------------------------------------- 7. SOLE VOTING POWER 2,721,747 (1) ------------------------------------------------------ Number Of Shares 8. SHARED VOTING POWER Beneficially Owned By -0- Each Reporting Person ------------------------------------------------------ With 9. SOLE DISPOSITIVE POWER 2,721,747 (1) ------------------------------------------------------ 10. SHARED DISPOSITIVE POWER -0- - -------------------------------------------------------------------------------- 11. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 2,721,747 - -------------------------------------------------------------------------------- 12. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES [_] - -------------------------------------------------------------------------------- 13. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 4.2% - -------------------------------------------------------------------------------- 14. TYPE OF REPORTING PERSON PN - -------------------------------------------------------------------------------- (1) Power is exercised through its sole general partner, SPO Advisory Partners, L.P.

Page 3 of 41 pages CUSIP No. 127055101 - -------------------------------------------------------------------------------- 1. NAME OF REPORTING PERSON SPO Advisory Partners, L.P. - -------------------------------------------------------------------------------- 2. CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP: (a) [_] (b) [X] - -------------------------------------------------------------------------------- 3. SEC Use Only - -------------------------------------------------------------------------------- 4. SOURCE OF FUNDS Not Applicable - -------------------------------------------------------------------------------- 5. CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e) [_] - -------------------------------------------------------------------------------- 6. CITIZENSHIP OR PLACE OF ORGANIZATION Delaware - -------------------------------------------------------------------------------- 7. SOLE VOTING POWER 2,721,747 (1)(2) ------------------------------------------------------ Number Of Shares 8. SHARED VOTING POWER Beneficially Owned By -0- Each Reporting Person ------------------------------------------------------ With 9. SOLE DISPOSITIVE POWER 2,721,747 (1)(2) ------------------------------------------------------ 10. SHARED DISPOSITIVE POWER -0- - -------------------------------------------------------------------------------- 11. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 2,721,747 - -------------------------------------------------------------------------------- 12. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES [_] - -------------------------------------------------------------------------------- 13. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 4.2% - -------------------------------------------------------------------------------- 14. TYPE OF REPORTING PERSON PN - -------------------------------------------------------------------------------- (1) Solely in its capacity as the sole general partner of SPO Partners II, L.P. (2) Power is exercised through its sole general partner, SPO Advisory Corp.

Page 4 of 41 pages CUSIP No. 127055101 - -------------------------------------------------------------------------------- 1. NAME OF REPORTING PERSON SPO Advisory Corp. - -------------------------------------------------------------------------------- 2. CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP: (a) [_] (b) [X] - -------------------------------------------------------------------------------- 3. SEC Use Only - -------------------------------------------------------------------------------- 4. SOURCE OF FUNDS Not Applicable - -------------------------------------------------------------------------------- 5. CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e) [_] - -------------------------------------------------------------------------------- 6. CITIZENSHIP OR PLACE OF ORGANIZATION Delaware - -------------------------------------------------------------------------------- 7. SOLE VOTING POWER 2,721,747 (1)(2) ------------------------------------------------------ Number Of Shares 8. SHARED VOTING POWER Beneficially Owned By -0- Each Reporting Person ------------------------------------------------------ With 9. SOLE DISPOSITIVE POWER 2,721,747 (1)(2) ------------------------------------------------------ 10. SHARED DISPOSITIVE POWER -0- - -------------------------------------------------------------------------------- 11. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 2,721,747 - -------------------------------------------------------------------------------- 12. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES [_] - -------------------------------------------------------------------------------- 13. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 4.2% - -------------------------------------------------------------------------------- 14. TYPE OF REPORTING PERSON CO - -------------------------------------------------------------------------------- (1) Solely in its capacity as the sole general partner of SPO Advisory Partners, L.P. with respect to such shares. (2) Power is exercised through its four controlling persons, John H. Scully, William E. Oberndorf, William J. Patterson and Edward H. McDermott.

Page 5 of 41 pages CUSIP No. 127055101 - -------------------------------------------------------------------------------- 1. NAME OF REPORTING PERSON John H. Scully - -------------------------------------------------------------------------------- 2. CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP: (a) [_] (b) [X] - -------------------------------------------------------------------------------- 3. SEC Use Only - -------------------------------------------------------------------------------- 4. SOURCE OF FUNDS Not Applicable - -------------------------------------------------------------------------------- 5. CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e) [_] - -------------------------------------------------------------------------------- 6. CITIZENSHIP OR PLACE OF ORGANIZATION USA - -------------------------------------------------------------------------------- 7. SOLE VOTING POWER -0- ------------------------------------------------------ Number Of Shares 8. SHARED VOTING POWER Beneficially Owned By 2,721,747 (1) Each Reporting Person ------------------------------------------------------ With 9. SOLE DISPOSITIVE POWER -0- ------------------------------------------------------ 10. SHARED DISPOSITIVE POWER 2,721,747 (1) - -------------------------------------------------------------------------------- 11. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 2,721,747 - -------------------------------------------------------------------------------- 12. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES [_] - -------------------------------------------------------------------------------- 13. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 4.2% - -------------------------------------------------------------------------------- 14. TYPE OF REPORTING PERSON IN - -------------------------------------------------------------------------------- (1) These shares may be deemed to be beneficially owned by Mr. Scully solely in his capacity as one of four controlling persons of SPO Advisory Corp.

Page 6 of 41 pages CUSIP No. 127055101 - -------------------------------------------------------------------------------- 1. NAME OF REPORTING PERSON William E. Oberndorf - -------------------------------------------------------------------------------- 2. CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP: (a) [_] (b) [X] - -------------------------------------------------------------------------------- 3. SEC Use Only - -------------------------------------------------------------------------------- 4. SOURCE OF FUNDS Not Applicable and PF - -------------------------------------------------------------------------------- 5. CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e) [_] - -------------------------------------------------------------------------------- 6. CITIZENSHIP OR PLACE OF ORGANIZATION USA - -------------------------------------------------------------------------------- 7. SOLE VOTING POWER 140,800 (1) ------------------------------------------------------ Number Of Shares 8. SHARED VOTING POWER Beneficially Owned By 3,055,397 (2) Each Reporting Person ------------------------------------------------------ With 9. SOLE DISPOSITIVE POWER 140,800 (1) ------------------------------------------------------ 10. SHARED DISPOSITIVE POWER 3,055,397 (2) - -------------------------------------------------------------------------------- 11. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 3,196,197 - -------------------------------------------------------------------------------- 12. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES [_] - -------------------------------------------------------------------------------- 13. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 4.9% - -------------------------------------------------------------------------------- 14. TYPE OF REPORTING PERSON IN - -------------------------------------------------------------------------------- (1) Of these shares, 30,800 shares are held in William E. Oberndorf's Individual Retirement Account, which is self-directed, 100,000 shares may be deemed to be beneficially owned by Mr. Oberndorf solely in his capacity as sole general partner of Oberndorf Family Partners, a family partnership, and 10,000 shares are owned by Mr. Oberndorf solely in his capacity as trustee for the account of his children. (2) Of these shares, 2,721,747 shares may be deemed to be beneficially owned by Mr. Oberndorf solely in his capacity as one of the four controlling persons of SPO Advisory Corp., and 333,650 shares may be deemed to be beneficially owned by Mr. Oberndorf solely in his capacity as a trustee of the William and Susan Oberndorf Trust, dated 10/19/98.

Page 7 of 41 pages CUSIP No. 127055101 - -------------------------------------------------------------------------------- 1. NAME OF REPORTING PERSON William and Susan Oberndorf Trust, dated 10/19/98 - -------------------------------------------------------------------------------- 2. CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP: (a) [_] (b) [X] - -------------------------------------------------------------------------------- 3. SEC Use Only - -------------------------------------------------------------------------------- 4. SOURCE OF FUNDS PF - -------------------------------------------------------------------------------- 5. CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e) [_] - -------------------------------------------------------------------------------- 6. CITIZENSHIP OR PLACE OF ORGANIZATION California - -------------------------------------------------------------------------------- 7. SOLE VOTING POWER 333,650 (1) ------------------------------------------------------ Number Of Shares 8. SHARED VOTING POWER Beneficially Owned By -0- Each Reporting Person ------------------------------------------------------ With 9. SOLE DISPOSITIVE POWER 333,650 (1) ------------------------------------------------------ 10. SHARED DISPOSITIVE POWER -0- - -------------------------------------------------------------------------------- 11. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 333,650 (1) - -------------------------------------------------------------------------------- 12. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES [_] - -------------------------------------------------------------------------------- 13. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 0.5% - -------------------------------------------------------------------------------- 14. TYPE OF REPORTING PERSON OO - -------------------------------------------------------------------------------- (1) Power is exercised through its trustees, William E. Oberndorf and Susan C. Oberndorf.

Page 8 of 41 pages CUSIP No. 127055101 - -------------------------------------------------------------------------------- 1. NAME OF REPORTING PERSON Oberndorf Family Partners - -------------------------------------------------------------------------------- 2. CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP: (a) [_] (b) [X] - -------------------------------------------------------------------------------- 3. SEC Use Only - -------------------------------------------------------------------------------- 4. SOURCE OF FUNDS WC - -------------------------------------------------------------------------------- 5. CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e) [_] - -------------------------------------------------------------------------------- 6. CITIZENSHIP OR PLACE OF ORGANIZATION California - -------------------------------------------------------------------------------- 7. SOLE VOTING POWER 100,000 (1) ------------------------------------------------------ Number Of Shares 8. SHARED VOTING POWER Beneficially Owned By -0- Each Reporting Person ------------------------------------------------------ With 9. SOLE DISPOSITIVE POWER 100,000 (1) ------------------------------------------------------ 10. SHARED DISPOSITIVE POWER -0- - -------------------------------------------------------------------------------- 11. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 100,000 (1) - -------------------------------------------------------------------------------- 12. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES [_] - -------------------------------------------------------------------------------- 13. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 0.2% - -------------------------------------------------------------------------------- 14. TYPE OF REPORTING PERSON PN - -------------------------------------------------------------------------------- (1) Power is exercised through its sole general partner, William E. Oberndorf.

Page 9 of 41 pages CUSIP No. 127055101 - -------------------------------------------------------------------------------- 1. NAME OF REPORTING PERSON William J. Patterson - -------------------------------------------------------------------------------- 2. CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP: (a) [_] (b) [X] - -------------------------------------------------------------------------------- 3. SEC Use Only - -------------------------------------------------------------------------------- 4. SOURCE OF FUNDS Not Applicable - -------------------------------------------------------------------------------- 5. CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e) [_] - -------------------------------------------------------------------------------- 6. CITIZENSHIP OR PLACE OF ORGANIZATION USA - -------------------------------------------------------------------------------- 7. SOLE VOTING POWER -0- ------------------------------------------------------ Number Of Shares 8. SHARED VOTING POWER Beneficially Owned By 2,727,847 (1) Each Reporting Person ------------------------------------------------------ With 9. SOLE DISPOSITIVE POWER -0- ------------------------------------------------------ 10. SHARED DISPOSITIVE POWER 2,727,847 (1) - -------------------------------------------------------------------------------- 11. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 2,727,847 - -------------------------------------------------------------------------------- 12. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES [_] - -------------------------------------------------------------------------------- 13. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 4.2% - -------------------------------------------------------------------------------- 14. TYPE OF REPORTING PERSON IN - -------------------------------------------------------------------------------- (1) Of these shares, 2,721,747 shares may be deemed to be beneficially owned by Mr. Patterson solely in his capacity as one of the four controlling persons of SPO Advisory Corp. and 6,100 shares may be deemed to be beneficially owned by Mr. Patterson solely in his capacity as a controlling person, director and executive officer of the Elizabeth R. & William J. Patterson Foundation.

Page 10 of 41 pages CUSIP No. 127055101 - -------------------------------------------------------------------------------- 1. NAME OF REPORTING PERSON The Elizabeth R. & William J. Patterson Foundation - -------------------------------------------------------------------------------- 2. CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP: (a) [_] (b) [X] - -------------------------------------------------------------------------------- 3. SEC Use Only - -------------------------------------------------------------------------------- 4. SOURCE OF FUNDS WC - -------------------------------------------------------------------------------- 5. CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e) [_] - -------------------------------------------------------------------------------- 6. CITIZENSHIP OR PLACE OF ORGANIZATION CALIFORNIA - -------------------------------------------------------------------------------- 7. SOLE VOTING POWER 6,100 (1) ------------------------------------------------------ Number Of Shares 8. SHARED VOTING POWER Beneficially Owned By -0- Each Reporting Person ------------------------------------------------------ With 9. SOLE DISPOSITIVE POWER 6,100 (1) ------------------------------------------------------ 10. SHARED DISPOSITIVE POWER -0- - -------------------------------------------------------------------------------- 11. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 6,100 - -------------------------------------------------------------------------------- 12. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES [_] - -------------------------------------------------------------------------------- 13. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) **0.1% - -------------------------------------------------------------------------------- 14. TYPE OF REPORTING PERSON CO - -------------------------------------------------------------------------------- ** Denotes less than. (1) Power is exercised through its controlling persons, directors and executive officers, William J. Patterson and Elizabeth R. Patterson.

Page 11 of 41 pages CUSIP No. 127055101 - -------------------------------------------------------------------------------- 1. NAME OF REPORTING PERSON Edward H. McDermott - -------------------------------------------------------------------------------- 2. CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP: (a) [_] (b) [X] - -------------------------------------------------------------------------------- 3. SEC Use Only - -------------------------------------------------------------------------------- 4. SOURCE OF FUNDS Not Applicable - -------------------------------------------------------------------------------- 5. CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e) [_] - -------------------------------------------------------------------------------- 6. CITIZENSHIP OR PLACE OF ORGANIZATION USA - -------------------------------------------------------------------------------- 7. SOLE VOTING POWER -0- ------------------------------------------------------ Number Of Shares 8. SHARED VOTING POWER Beneficially Owned By 2,721,747 (1) Each Reporting Person ------------------------------------------------------ With 9. SOLE DISPOSITIVE POWER -0- ------------------------------------------------------ 10. SHARED DISPOSITIVE POWER 2,721,747 (1) - -------------------------------------------------------------------------------- 11. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 2,721,747 - -------------------------------------------------------------------------------- 12. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES [_] - -------------------------------------------------------------------------------- 13. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 4.2% - -------------------------------------------------------------------------------- 14. TYPE OF REPORTING PERSON IN - -------------------------------------------------------------------------------- (1) These shares may be deemed to be beneficially owned by Mr. McDermott solely in his capacity as one of four controlling persons of SPO Advisory Corp.

Page 12 of 41 pages CUSIP No. 127055101 - -------------------------------------------------------------------------------- 1. NAME OF REPORTING PERSON Ian R. McGuire - -------------------------------------------------------------------------------- 2. CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP: (a) [_] (b) [X] - -------------------------------------------------------------------------------- 3. SEC Use Only - -------------------------------------------------------------------------------- 4. SOURCE OF FUNDS PF - -------------------------------------------------------------------------------- 5. CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e) [_] - -------------------------------------------------------------------------------- 6. CITIZENSHIP OR PLACE OF ORGANIZATION CALIFORNIA - -------------------------------------------------------------------------------- 7. SOLE VOTING POWER 475 ------------------------------------------------------ Number Of Shares 8. SHARED VOTING POWER Beneficially Owned By -0- Each Reporting Person ------------------------------------------------------ With 9. SOLE DISPOSITIVE POWER 475 ------------------------------------------------------ 10. SHARED DISPOSITIVE POWER -0- - -------------------------------------------------------------------------------- 11. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 475 - -------------------------------------------------------------------------------- 12. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES [_] - -------------------------------------------------------------------------------- 13. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) **0.1% - -------------------------------------------------------------------------------- 14. TYPE OF REPORTING PERSON IN - -------------------------------------------------------------------------------- ** Denotes less than.

Page 13 of 41 pages CUSIP No. 127055101 - -------------------------------------------------------------------------------- 1. NAME OF REPORTING PERSON Betty Jane Weimer - -------------------------------------------------------------------------------- 2. CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP: (a) [_] (b) [X] - -------------------------------------------------------------------------------- 3. SEC Use Only - -------------------------------------------------------------------------------- 4. SOURCE OF FUNDS PF - -------------------------------------------------------------------------------- 5. CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e) [_] - -------------------------------------------------------------------------------- 6. CITIZENSHIP OR PLACE OF ORGANIZATION California - -------------------------------------------------------------------------------- 7. SOLE VOTING POWER 5,000 ------------------------------------------------------ Number Of Shares 8. SHARED VOTING POWER Beneficially Owned By -0- Each Reporting Person ------------------------------------------------------ With 9. SOLE DISPOSITIVE POWER 5,000 ------------------------------------------------------ 10. SHARED DISPOSITIVE POWER -0- - -------------------------------------------------------------------------------- 11. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 5,000 - -------------------------------------------------------------------------------- 12. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES [_] - -------------------------------------------------------------------------------- 13. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) **0.1% - -------------------------------------------------------------------------------- 14. TYPE OF REPORTING PERSON IN - -------------------------------------------------------------------------------- ** Denotes less than.

Page 14 of 41 pages This Amendment No. 13 amends the Schedule 13D (the "Original 13D") filed with the Securities and Exchange Commission ("SEC") on August 29, 2005 and as amended on September 14, 2005, September 26, 2005, October 20, 2005, November 8, 2005, January 12, 2006, June 20, 2006, December 18, 2007, January 4, 2008, August 12, 2008, June 1, 2009, August 5, 2009 and August 12, 2009. Unless otherwise stated herein, the Original 13D, as previously amended, remains in full force and effect. Terms used herein and not defined herein shall have the meanings ascribed thereto in the Original 13D. ITEM 2. IDENTITY AND BACKGROUND. Item 2(a) is hereby amended and restated in its entirety as follows: (a) The undersigned hereby file this Schedule 13D Statement on behalf of SPO Partners II, L.P., a Delaware limited partnership ("SPO"), SPO Advisory Partners, L.P., a Delaware limited partnership ("SPO Advisory Partners"), SPO Advisory Corp., a Delaware corporation ("SPO Advisory Corp."), John H. Scully ("JHS"), William E. Oberndorf ("WEO"), William J. Patterson ("WJP"), Edward H. McDermott ("EHM"), the William and Susan Oberndorf Trust, dated 10/19/98 ("Oberndorf Trust"), Oberndorf Family Partners, a California limited partnership ("OFP"), the Elizabeth R. & William J. Patterson Foundation, a California corporation ("Patterson Foundation"), Ian R. McGuire ("IRM") and Betty Jane Weimer ("BJW"). SPO, SPO Advisory Partners, SPO Advisory Corp., JHS, WEO, WJP, EHM, the Oberndorf Trust, OFP, Patterson Foundation, IRM and BJW are sometimes hereinafter referred to as the "Reporting Persons." The Reporting Persons are making this single, joint filing because they may be deemed to constitute a "group" within the meaning of Section 13(d)(3) of the Securities Exchange Act of 1934, as amended (the "Act"), although neither the fact of this filing nor anything contained herein shall be deemed to be an admission by the Reporting Persons that a group exists.

Page 15 of 41 pages ITEM 3. SOURCE AND AMOUNT OF FUNDS OR OTHER CONSIDERATION. Item 3 is hereby amended and restated in its entirety as follows: The source and amount of the funds used or to be used by the Reporting Persons to purchase Shares are as follows: NAME SOURCE OF FUNDS AMOUNT OF FUNDS - --------------------- --------------------------- --------------- SPO Contributions from Partners $192,225,087 SPO Advisory Partners Not Applicable Not Applicable SPO Advisory Corp. Not Applicable Not Applicable JHS Not Applicable Not Applicable WEO Not Applicable and Personal Funds (1) $ 4,036,047 WJP Not Applicable Not Applicable EHM Not Applicable Not Applicable Oberndorf Trust Personal Funds (1) $ 12,237,424 OFP Contribution from Partners $ 3,635,448 Patterson Foundation Contributions from Shareholders $ 444,299 IRM Personal Funds (1) $ 16,877 BJW Personal Funds (1) $ 186,594 - ---------- (1) As used herein, the term "Personal Funds" includes sums borrowed from banks and brokerage firm margin accounts, none of which were borrowed or otherwise obtained for the specified purpose of acquiring, holding, trading or voting Shares. ITEM 5. INTEREST IN SECURITIES OF THE ISSUER. Item 5 is hereby amended and restated in its entirety as follows: (a) Percentage interest calculations for each Reporting Person are based upon the Issuer having 65,382,796 total outstanding shares of Common Stock as reported on the Issuer's 10-Q filed with the Securities and Exchange Commission on August 10, 2009. SPO The aggregate number of Shares that SPO owns beneficially, pursuant to Rule 13d-3 of the Act, is 2,721,747 Shares, which constitutes approximately 4.2% of the outstanding Shares. SPO Advisory Partners Because of its position as the sole general partner of SPO, SPO Advisory Partners may, pursuant to Rule 13d-3 of the Act, be deemed to be the beneficial owner of 2,721,747 Shares, which constitutes approximately 4.2% of the outstanding Shares. SPO Advisory Corp. Because of its position as the sole general partner of SPO Advisory Partners, SPO Advisory Corp. may, pursuant to Rule 13d-3 of the Act, be deemed to be the beneficial owner of 2,721,747 Shares in the aggregate, which constitutes approximately 4.2% of the outstanding Shares. JHS Because of his position as a control person of SPO Advisory Corp., JHS may, pursuant to Rule 13d-3 of the Act, be deemed to be the beneficial owner of 2,721,747 Shares, which constitutes approximately 4.2% of the outstanding Shares. WEO Individually, and because of his positions as a control person of SPO Advisory Corp., a trustee of the Oberndorf Trust and sole general partner of OFP and as trustee for the account of his children, WEO may, pursuant to Rule 13d-3 of the Act, be deemed to be the beneficial owner of 3,196,197 Shares in the aggregate, which constitutes approximately 4.9% of the outstanding Shares.

Page 16 of 41 pages WJP Because of his position as a control person of SPO Advisory Corp. and as a control person, director and executive officer of Patterson Foundation, WJP may, pursuant to Rule 13d-3 of the Act, be deemed to be the beneficial owner of 2,727,847 Shares, which constitutes approximately 4.2% of the outstanding Shares. EHM Because of his position as a control person of SPO Advisory Corp., EHM may, pursuant to Rule 13d-3 of the Act, be deemed to be the beneficial owner of 2,721,747 Shares, which constitutes approximately 4.2% of the outstanding Shares. Oberndorf Trust The aggregate number of Shares that the Oberndorf Trust owns beneficially, pursuant to Rule 13d-3 of the Act, is 333,650 Shares, which constitutes approximately 0.5% of the outstanding Shares. OFP The aggregate number of Shares that OFP owns beneficially, pursuant to Rule 13d-3 of the Act, is 100,000 Shares, which constitutes approximately 0.2% of the outstanding Shares. Patterson Foundation The aggregate number of Shares that Patterson Foundation owns beneficially, pursuant to Rule 13d-3 of the Act, is 6,100, which constitutes less than 0.1% of the outstanding Shares. IRM The aggregate number of Shares that IRM owns beneficially, pursuant to Rule 13d-3 of the Act, is 475 Shares, which constitutes less than 0.1% of the outstanding Shares. BJW The aggregate number of Shares that BJW owns beneficially, pursuant to Rule 13d-3 of the Act, is 5,000 Shares, which constitutes less than 0.1% of the outstanding Shares. To the best of the knowledge of each of the Reporting Persons, other than as set forth above, none of the persons named in Item 2 hereof is the beneficial owner of any Shares. (b) SPO Acting through its sole general partner, SPO has the sole power to vote or to direct the vote and to dispose or to direct the disposition of 2,721,747 Shares. SPO Advisory Partners Acting through its sole general partner and in its capacity as the sole general partner of SPO, SPO Advisory Partners has the sole power to vote or to direct the vote and to dispose or to direct the disposition of 2,721,747 Shares.

Page 17 of 41 pages SPO Advisory Corp. Acting through its controlling persons and in its capacity as the sole general partner of SPO Advisory Partners, SPO Advisory Corp. has the sole power to vote or to direct the vote and to dispose or to direct the disposition of 2,721,747 Shares in the aggregate. JHS As one of four controlling persons of SPO Advisory Corp., which is the sole general partner of SPO Advisory Partners, JHS may be deemed to have shared power with WEO, WJP and EHM to vote or to direct the vote and to dispose or to direct the disposition of 2,721,747 Shares held by SPO. WEO As one of four controlling persons of SPO Advisory Corp., which is the sole general partner of SPO Advisory Partners, WEO may be deemed to have shared power with JHS, WJP and EHM to vote or to direct the vote and to dispose or to direct the disposition of 2,721,747 Shares held by SPO. WEO may be deemed to have shared power to vote or to direct the vote and to dispose or to direct the disposition of 333,650 Shares held in the Oberndorf Trust. Individually, and because of his position as the sole general partner of OFP, WEO has the sole power to vote or to direct the vote and to dispose or to direct the disposition of 30,800 Shares held in WEO's Individual Retirement Account, which is self directed, and 100,000 Shares held by OFP. Solely in his capacity as trustee for the account of his children, WEO has the sole power to vote or to direct the vote and to dispose or to direct the disposition of 10,000 shares owned by his children. WJP As one of four controlling persons of SPO Advisory Corp., which is the sole general partner of SPO Advisory Partners, WJP may be deemed to have shared power with JHS, WEO and EHM to vote or to direct the vote and to dispose or to direct the disposition of 2,721,747 Shares held by SPO. WJP may be deemed to have shared power to vote or to direct the vote and to dispose or to direct the disposition of 6,100 Shares held by the Patterson Foundation. EHM As one of four controlling persons of SPO Advisory Corp., which is the sole general partner of SPO Advisory Partners, EHM may be deemed to have shared power with JHS, WEO and WJP to vote or to direct the vote and to dispose or to direct the disposition of 2,721,747 Shares held by SPO.

Page 18 of 41 pages Oberndorf Trust Acting through its trustees, Oberndorf Trust has the sole power to vote or to direct the vote and to dispose or to direct the disposition of 333,650 Shares in the aggregate. OFP OFP has the sole power to vote or to direct the vote and to dispose or to direct the disposition of 100,000 Shares. Patterson Foundation Acting through its two controlling persons, directors and executive officers, Patterson Foundation has the sole power to vote or to direct the vote and to dispose or to direct the disposition of 6,100 Shares. IRM IRM has the sole power to vote or to direct the vote and to dispose or to direct the disposition of 475 Shares. BJW BJW has the sole power to vote or to direct the vote and to dispose or to direct the disposition of 5,000 Shares. (c) Since the most recent filing on Schedule 13D, the Reporting Persons sold Shares in open market transactions as set forth on Schedule I attached hereto. Except as set forth in this paragraph (c), to the best of the knowledge of each of the Reporting Persons, none of the persons named in response to paragraph (a) has effected any transactions in Shares since the most recent filing on Schedule 13D. (d) Each of the Reporting Persons affirms that no person other than such Reporting Person has the right to receive or the power to direct the receipt of distributions with respect to, or the proceeds from the sale of, Shares owned by such Reporting Person. (e) The Reporting Persons ceased to be the holders of more than 5% of the outstanding shares of the Issuer on August 19, 2009. ITEM 7. MATERIAL TO BE FILED AS EXHIBITS. Item 7 is hereby amended and restated in its entirety as follows: Exhibit A: Agreement pursuant to Rule 13d-1(k)

Page 19 of 41 pages SIGNATURE After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct. Dated August 21, 2009 By: /s/ Kim M. Silva -------------------------------- Kim M. Silva Attorney-in-Fact for: SPO PARTNERS II, L.P.(1) SPO ADVISORY PARTNERS, L.P.(1) SPO ADVISORY CORP.(1) JOHN H. SCULLY(1) WILLIAM E. OBERNDORF(1) WILLIAM J. PATTERSON(1) EDWARD H. MCDERMOTT(1) WILLIAM AND SUSAN OBERNDORF TRUST, DATED 10/19/98 (1) OBERNDORF FAMILY PARTNERS (1) THE ELIZABETH R. & WILLIAM J. PATTERSON FOUNDATION (1) IAN R. MCGUIRE (1) BETTY JANE WEIMER (1) (1) A Power of Attorney authorizing Kim M. Silva to act on behalf of this person or entity has been previously filed with the Securities and Exchange Commission.

Page 20 of 41 pages SCHEDULE I TO SCHEDULE 13D DATE OF NUMBER OF PRICE PER WHERE/HOW TRANSACTION REPORTING PERSON TRANSACTION TYPE SHARES SHARE $ EFFECTED - ---------------------------------------- ----------- ---- --------- --------- ---------------------- SPO Partners II, L.P. 08/12/09 Sell 99 19.73 Open Market/Broker SPO Partners II, L.P. 08/12/09 Sell 592 19.76 Open Market/Broker SPO Partners II, L.P. 08/12/09 Sell 198 19.79 Open Market/Broker SPO Partners II, L.P. 08/12/09 Sell 45 19.81 Open Market/Broker SPO Partners II, L.P. 08/12/09 Sell 99 19.82 Open Market/Broker SPO Partners II, L.P. 08/12/09 Sell 43 19.84 Open Market/Broker SPO Partners II, L.P. 08/12/09 Sell 53 19.85 Open Market/Broker SPO Partners II, L.P. 08/12/09 Sell 944 19.86 Open Market/Broker SPO Partners II, L.P. 08/12/09 Sell 99 19.87 Open Market/Broker SPO Partners II, L.P. 08/12/09 Sell 787 19.88 Open Market/Broker SPO Partners II, L.P. 08/12/09 Sell 1,386 19.89 Open Market/Broker SPO Partners II, L.P. 08/12/09 Sell 592 19.90 Open Market/Broker SPO Partners II, L.P. 08/12/09 Sell 1,184 19.91 Open Market/Broker SPO Partners II, L.P. 08/12/09 Sell 888 19.92 Open Market/Broker SPO Partners II, L.P. 08/12/09 Sell 877 19.93 Open Market/Broker SPO Partners II, L.P. 08/12/09 Sell 4,249 19.94 Open Market/Broker SPO Partners II, L.P. 08/12/09 Sell 1,209 19.95 Open Market/Broker SPO Partners II, L.P. 08/12/09 Sell 3,955 19.96 Open Market/Broker SPO Partners II, L.P. 08/12/09 Sell 3,831 19.97 Open Market/Broker SPO Partners II, L.P. 08/12/09 Sell 1,672 19.98 Open Market/Broker SPO Partners II, L.P. 08/12/09 Sell 5,328 19.99 Open Market/Broker SPO Partners II, L.P. 08/12/09 Sell 5,614 20.00 Open Market/Broker SPO Partners II, L.P. 08/12/09 Sell 4,279 20.01 Open Market/Broker SPO Partners II, L.P. 08/12/09 Sell 7,063 20.02 Open Market/Broker SPO Partners II, L.P. 08/12/09 Sell 4,292 20.03 Open Market/Broker SPO Partners II, L.P. 08/12/09 Sell 6,707 20.04 Open Market/Broker SPO Partners II, L.P. 08/12/09 Sell 4,613 20.05 Open Market/Broker SPO Partners II, L.P. 08/12/09 Sell 8,041 20.06 Open Market/Broker SPO Partners II, L.P. 08/12/09 Sell 6,713 20.07 Open Market/Broker SPO Partners II, L.P. 08/12/09 Sell 7,211 20.08 Open Market/Broker SPO Partners II, L.P. 08/12/09 Sell 13,755 20.09 Open Market/Broker SPO Partners II, L.P. 08/12/09 Sell 26,547 20.10 Open Market/Broker SPO Partners II, L.P. 08/12/09 Sell 7,805 20.11 Open Market/Broker SPO Partners II, L.P. 08/12/09 Sell 1,898 20.12 Open Market/Broker SPO Partners II, L.P. 08/12/09 Sell 5,069 20.13 Open Market/Broker SPO Partners II, L.P. 08/12/09 Sell 987 20.14 Open Market/Broker SPO Partners II, L.P. 08/12/09 Sell 2,669 20.15 Open Market/Broker SPO Partners II, L.P. 08/12/09 Sell 4,911 20.02 Open Market/Broker SPO Partners II, L.P. 08/12/09 Sell 8,027 20.17 Open Market/Broker SPO Partners II, L.P. 08/12/09 Sell 7,313 20.18 Open Market/Broker SPO Partners II, L.P. 08/12/09 Sell 12,100 20.19 Open Market/Broker SPO Partners II, L.P. 08/12/09 Sell 13,234 20.20 Open Market/Broker SPO Partners II, L.P. 08/12/09 Sell 2,268 20.21 Open Market/Broker

Page 21 of 41 pages SCHEDULE I TO SCHEDULE 13D DATE OF NUMBER OF PRICE PER WHERE/HOW TRANSACTION REPORTING PERSON TRANSACTION TYPE SHARES SHARE $ EFFECTED - ---------------------------------------- ----------- ---- --------- --------- ---------------------- SPO Partners II, L.P. 08/12/09 Sell 1,592 20.22 Open Market/Broker SPO Partners II, L.P. 08/12/09 Sell 387 20.23 Open Market/Broker SPO Partners II, L.P. 08/12/09 Sell 1,128 20.24 Open Market/Broker SPO Partners II, L.P. 08/12/09 Sell 2,034 20.25 Open Market/Broker SPO Partners II, L.P. 08/12/09 Sell 3,361 20.26 Open Market/Broker SPO Partners II, L.P. 08/12/09 Sell 2,586 20.27 Open Market/Broker SPO Partners II, L.P. 08/12/09 Sell 917 20.28 Open Market/Broker SPO Partners II, L.P. 08/12/09 Sell 1,698 20.29 Open Market/Broker SPO Partners II, L.P. 08/12/09 Sell 1,973 20.33 Open Market/Broker SPO Partners II, L.P. 08/12/09 Sell 1,178 20.34 Open Market/Broker SPO Partners II, L.P. 08/12/09 Sell 100 20.36 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 08/12/09 Sell 1 19.76 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 08/12/09 Sell 2 19.86 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 08/12/09 Sell 2 19.88 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 08/12/09 Sell 3 19.89 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 08/12/09 Sell 1 19.90 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 08/12/09 Sell 3 19.91 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 08/12/09 Sell 2 19.92 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 08/12/09 Sell 2 19.93 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 08/12/09 Sell 10 19.94 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 08/12/09 Sell 3 19.95 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 08/12/09 Sell 10 19.96 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 08/12/09 Sell 9 19.97 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 08/12/09 Sell 4 19.98 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 08/12/09 Sell 13 19.99 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 08/12/09 Sell 14 20.00 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 08/12/09 Sell 10 20.01 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 08/12/09 Sell 17 20.02 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 08/12/09 Sell 10 20.03 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 08/12/09 Sell 16 20.04 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 08/12/09 Sell 11 20.05 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 08/12/09 Sell 19 20.06 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 08/12/09 Sell 16 20.07 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 08/12/09 Sell 17 20.08 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 08/12/09 Sell 33 20.09 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 08/12/09 Sell 64 20.10 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 08/12/09 Sell 19 20.11 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 08/12/09 Sell 5 20.12 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 08/12/09 Sell 12 20.13 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 08/12/09 Sell 2 20.14 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 08/12/09 Sell 6 20.15 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 08/12/09 Sell 12 20.02 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 08/12/09 Sell 19 20.17 Open Market/Broker

Page 22 of 41 pages SCHEDULE I TO SCHEDULE 13D DATE OF NUMBER OF PRICE PER WHERE/HOW TRANSACTION REPORTING PERSON TRANSACTION TYPE SHARES SHARE $ EFFECTED - ---------------------------------------- ----------- ---- --------- --------- ---------------------- The Elizabeth R. and William J. Patterson Foundation 08/12/09 Sell 18 20.18 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 08/12/09 Sell 29 20.19 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 08/12/09 Sell 32 20.20 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 08/12/09 Sell 6 20.21 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 08/12/09 Sell 4 20.22 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 08/12/09 Sell 1 20.23 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 08/12/09 Sell 3 20.24 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 08/12/09 Sell 5 20.25 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 08/12/09 Sell 8 20.26 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 08/12/09 Sell 6 20.27 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 08/12/09 Sell 2 20.28 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 08/12/09 Sell 4 20.29 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 08/12/09 Sell 5 20.33 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 08/12/09 Sell 10 20.34 Open Market/Broker William E. Oberndorf IRA 08/12/09 Sell 1 19.73 Open Market/Broker William E. Oberndorf IRA 08/12/09 Sell 7 19.76 Open Market/Broker William E. Oberndorf IRA 08/12/09 Sell 2 19.79 Open Market/Broker William E. Oberndorf IRA 08/12/09 Sell 1 19.81 Open Market/Broker William E. Oberndorf IRA 08/12/09 Sell 1 19.82 Open Market/Broker William E. Oberndorf IRA 08/12/09 Sell 1 19.85 Open Market/Broker William E. Oberndorf IRA 08/12/09 Sell 11 19.86 Open Market/Broker William E. Oberndorf IRA 08/12/09 Sell 1 19.87 Open Market/Broker William E. Oberndorf IRA 08/12/09 Sell 9 19.88 Open Market/Broker William E. Oberndorf IRA 08/12/09 Sell 15 19.89 Open Market/Broker William E. Oberndorf IRA 08/12/09 Sell 7 19.90 Open Market/Broker William E. Oberndorf IRA 08/12/09 Sell 13 19.91 Open Market/Broker William E. Oberndorf IRA 08/12/09 Sell 10 19.92 Open Market/Broker William E. Oberndorf IRA 08/12/09 Sell 10 19.93 Open Market/Broker William E. Oberndorf IRA 08/12/09 Sell 47 19.94 Open Market/Broker William E. Oberndorf IRA 08/12/09 Sell 13 19.95 Open Market/Broker William E. Oberndorf IRA 08/12/09 Sell 44 19.96 Open Market/Broker William E. Oberndorf IRA 08/12/09 Sell 43 19.97 Open Market/Broker William E. Oberndorf IRA 08/12/09 Sell 19 19.98 Open Market/Broker William E. Oberndorf IRA 08/12/09 Sell 59 19.99 Open Market/Broker William E. Oberndorf IRA 08/12/09 Sell 63 20.00 Open Market/Broker William E. Oberndorf IRA 08/12/09 Sell 48 20.01 Open Market/Broker William E. Oberndorf IRA 08/12/09 Sell 79 20.02 Open Market/Broker William E. Oberndorf IRA 08/12/09 Sell 48 20.03 Open Market/Broker William E. Oberndorf IRA 08/12/09 Sell 75 20.04 Open Market/Broker William E. Oberndorf IRA 08/12/09 Sell 51 20.05 Open Market/Broker William E. Oberndorf IRA 08/12/09 Sell 90 20.06 Open Market/Broker William E. Oberndorf IRA 08/12/09 Sell 75 20.07 Open Market/Broker William E. Oberndorf IRA 08/12/09 Sell 80 20.08 Open Market/Broker

Page 23 of 41 pages SCHEDULE I TO SCHEDULE 13D DATE OF NUMBER OF PRICE PER WHERE/HOW TRANSACTION REPORTING PERSON TRANSACTION TYPE SHARES SHARE $ EFFECTED - ---------------------------------------- ----------- ---- --------- --------- ---------------------- William E. Oberndorf IRA 08/12/09 Sell 153 20.09 Open Market/Broker William E. Oberndorf IRA 08/12/09 Sell 296 20.10 Open Market/Broker William E. Oberndorf IRA 08/12/09 Sell 87 20.11 Open Market/Broker William E. Oberndorf IRA 08/12/09 Sell 21 20.12 Open Market/Broker William E. Oberndorf IRA 08/12/09 Sell 57 20.13 Open Market/Broker William E. Oberndorf IRA 08/12/09 Sell 11 20.14 Open Market/Broker William E. Oberndorf IRA 08/12/09 Sell 30 20.15 Open Market/Broker William E. Oberndorf IRA 08/12/09 Sell 55 20.02 Open Market/Broker William E. Oberndorf IRA 08/12/09 Sell 90 20.17 Open Market/Broker William E. Oberndorf IRA 08/12/09 Sell 82 20.18 Open Market/Broker William E. Oberndorf IRA 08/12/09 Sell 135 20.19 Open Market/Broker William E. Oberndorf IRA 08/12/09 Sell 148 20.20 Open Market/Broker William E. Oberndorf IRA 08/12/09 Sell 25 20.21 Open Market/Broker William E. Oberndorf IRA 08/12/09 Sell 18 20.22 Open Market/Broker William E. Oberndorf IRA 08/12/09 Sell 4 20.23 Open Market/Broker William E. Oberndorf IRA 08/12/09 Sell 13 20.24 Open Market/Broker William E. Oberndorf IRA 08/12/09 Sell 23 20.25 Open Market/Broker William E. Oberndorf IRA 08/12/09 Sell 37 20.26 Open Market/Broker William E. Oberndorf IRA 08/12/09 Sell 29 20.27 Open Market/Broker William E. Oberndorf IRA 08/12/09 Sell 10 20.28 Open Market/Broker William E. Oberndorf IRA 08/12/09 Sell 19 20.29 Open Market/Broker William E. Oberndorf IRA 08/12/09 Sell 22 20.33 Open Market/Broker William E. Oberndorf IRA 08/12/09 Sell 12 20.34 Open Market/Broker SPO Partners II, L.P. 8/13/09 Sell 6,017 20.00 Open Market/Broker SPO Partners II, L.P. 8/13/09 Sell 3,373 20.01 Open Market/Broker SPO Partners II, L.P. 8/13/09 Sell 1,895 20.02 Open Market/Broker SPO Partners II, L.P. 8/13/09 Sell 2,567 20.03 Open Market/Broker SPO Partners II, L.P. 8/13/09 Sell 3,260 20.04 Open Market/Broker SPO Partners II, L.P. 8/13/09 Sell 3,754 20.05 Open Market/Broker SPO Partners II, L.P. 8/13/09 Sell 2,069 20.06 Open Market/Broker SPO Partners II, L.P. 8/13/09 Sell 2,193 20.07 Open Market/Broker SPO Partners II, L.P. 8/13/09 Sell 2,988 20.08 Open Market/Broker SPO Partners II, L.P. 8/13/09 Sell 13,163 20.09 Open Market/Broker SPO Partners II, L.P. 8/13/09 Sell 13,685 20.10 Open Market/Broker SPO Partners II, L.P. 8/13/09 Sell 6,587 20.11 Open Market/Broker SPO Partners II, L.P. 8/13/09 Sell 5,722 20.12 Open Market/Broker SPO Partners II, L.P. 8/13/09 Sell 2,934 20.13 Open Market/Broker SPO Partners II, L.P. 8/13/09 Sell 3,850 20.14 Open Market/Broker SPO Partners II, L.P. 8/13/09 Sell 1,142 20.15 Open Market/Broker SPO Partners II, L.P. 8/13/09 Sell 3,975 20.16 Open Market/Broker SPO Partners II, L.P. 8/13/09 Sell 1,081 20.17 Open Market/Broker SPO Partners II, L.P. 8/13/09 Sell 2,546 20.18 Open Market/Broker SPO Partners II, L.P. 8/13/09 Sell 2,588 20.19 Open Market/Broker

Page 24 of 41 pages SCHEDULE I TO SCHEDULE 13D DATE OF NUMBER OF PRICE PER WHERE/HOW TRANSACTION REPORTING PERSON TRANSACTION TYPE SHARES SHARE $ EFFECTED - ---------------------------------------- ----------- ---- --------- --------- ---------------------- SPO Partners II, L.P. 8/13/09 Sell 3,833 20.20 Open Market/Broker SPO Partners II, L.P. 8/13/09 Sell 4,314 20.21 Open Market/Broker SPO Partners II, L.P. 8/13/09 Sell 1,185 20.22 Open Market/Broker SPO Partners II, L.P. 8/13/09 Sell 1,889 20.23 Open Market/Broker SPO Partners II, L.P. 8/13/09 Sell 494 20.24 Open Market/Broker SPO Partners II, L.P. 8/13/09 Sell 102 20.25 Open Market/Broker SPO Partners II, L.P. 8/13/09 Sell 590 20.26 Open Market/Broker SPO Partners II, L.P. 8/13/09 Sell 1,520 20.27 Open Market/Broker SPO Partners II, L.P. 8/13/09 Sell 198 20.28 Open Market/Broker SPO Partners II, L.P. 8/13/09 Sell 589 20.29 Open Market/Broker SPO Partners II, L.P. 8/13/09 Sell 100 20.30 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/13/09 Sell 12 20.00 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/13/09 Sell 7 20.01 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/13/09 Sell 4 20.02 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/13/09 Sell 5 20.03 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/13/09 Sell 7 20.04 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/13/09 Sell 7 20.05 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/13/09 Sell 4 20.06 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/13/09 Sell 4 20.07 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/13/09 Sell 6 20.08 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/13/09 Sell 26 20.09 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/13/09 Sell 27 20.10 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/13/09 Sell 13 20.11 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/13/09 Sell 11 20.12 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/13/09 Sell 6 20.13 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/13/09 Sell 8 20.14 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/13/09 Sell 2 20.15 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/13/09 Sell 8 20.16 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/13/09 Sell 2 20.17 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/13/09 Sell 5 20.18 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/13/09 Sell 5 20.19 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/13/09 Sell 8 20.20 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/13/09 Sell 9 20.21 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/13/09 Sell 2 20.22 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/13/09 Sell 4 20.23 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/13/09 Sell 1 20.24 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/13/09 Sell 1 20.26 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/13/09 Sell 3 20.27 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/13/09 Sell 3 20.29 Open Market/Broker William E. Oberndorf IRA 8/13/09 Sell 66 20.00 Open Market/Broker William E. Oberndorf IRA 8/13/09 Sell 37 20.01 Open Market/Broker William E. Oberndorf IRA 8/13/09 Sell 21 20.02 Open Market/Broker William E. Oberndorf IRA 8/13/09 Sell 28 20.03 Open Market/Broker

Page 25 of 41 pages SCHEDULE I TO SCHEDULE 13D DATE OF NUMBER OF PRICE PER WHERE/HOW TRANSACTION REPORTING PERSON TRANSACTION TYPE SHARES SHARE $ EFFECTED - ---------------------------------------- ----------- ---- --------- --------- ---------------------- William E. Oberndorf IRA 8/13/09 Sell 36 20.04 Open Market/Broker William E. Oberndorf IRA 8/13/09 Sell 41 20.05 Open Market/Broker William E. Oberndorf IRA 8/13/09 Sell 23 20.06 Open Market/Broker William E. Oberndorf IRA 8/13/09 Sell 24 20.07 Open Market/Broker William E. Oberndorf IRA 8/13/09 Sell 33 20.08 Open Market/Broker William E. Oberndorf IRA 8/13/09 Sell 145 20.09 Open Market/Broker William E. Oberndorf IRA 8/13/09 Sell 150 20.10 Open Market/Broker William E. Oberndorf IRA 8/13/09 Sell 72 20.11 Open Market/Broker William E. Oberndorf IRA 8/13/09 Sell 63 20.12 Open Market/Broker William E. Oberndorf IRA 8/13/09 Sell 32 20.13 Open Market/Broker William E. Oberndorf IRA 8/13/09 Sell 42 20.14 Open Market/Broker William E. Oberndorf IRA 8/13/09 Sell 13 20.15 Open Market/Broker William E. Oberndorf IRA 8/13/09 Sell 44 20.16 Open Market/Broker William E. Oberndorf IRA 8/13/09 Sell 12 20.17 Open Market/Broker William E. Oberndorf IRA 8/13/09 Sell 28 20.18 Open Market/Broker William E. Oberndorf IRA 8/13/09 Sell 28 20.19 Open Market/Broker William E. Oberndorf IRA 8/13/09 Sell 42 20.20 Open Market/Broker William E. Oberndorf IRA 8/13/09 Sell 47 20.21 Open Market/Broker William E. Oberndorf IRA 8/13/09 Sell 13 20.22 Open Market/Broker William E. Oberndorf IRA 8/13/09 Sell 21 20.23 Open Market/Broker William E. Oberndorf IRA 8/13/09 Sell 5 20.24 Open Market/Broker William E. Oberndorf IRA 8/13/09 Sell 1 20.25 Open Market/Broker William E. Oberndorf IRA 8/13/09 Sell 6 20.26 Open Market/Broker William E. Oberndorf IRA 8/13/09 Sell 17 20.27 Open Market/Broker William E. Oberndorf IRA 8/13/09 Sell 2 20.28 Open Market/Broker William E. Oberndorf IRA 8/13/09 Sell 8 20.29 Open Market/Broker SPO Partners II, L.P. 8/14/09 Sell 13,294 19.75 Open Market/Broker SPO Partners II, L.P. 8/14/09 Sell 8,357 19.76 Open Market/Broker SPO Partners II, L.P. 8/14/09 Sell 4,042 19.77 Open Market/Broker SPO Partners II, L.P. 8/14/09 Sell 5,483 19.78 Open Market/Broker SPO Partners II, L.P. 8/14/09 Sell 6,151 19.79 Open Market/Broker SPO Partners II, L.P. 8/14/09 Sell 6,700 19.80 Open Market/Broker SPO Partners II, L.P. 8/14/09 Sell 5,576 19.81 Open Market/Broker SPO Partners II, L.P. 8/14/09 Sell 1,789 19.82 Open Market/Broker SPO Partners II, L.P. 8/14/09 Sell 2,583 19.83 Open Market/Broker SPO Partners II, L.P. 8/14/09 Sell 2,332 19.84 Open Market/Broker SPO Partners II, L.P. 8/14/09 Sell 3,300 19.85 Open Market/Broker SPO Partners II, L.P. 8/14/09 Sell 2,983 19.86 Open Market/Broker SPO Partners II, L.P. 8/14/09 Sell 3,702 19.87 Open Market/Broker SPO Partners II, L.P. 8/14/09 Sell 1,283 19.88 Open Market/Broker SPO Partners II, L.P. 8/14/09 Sell 2,176 19.89 Open Market/Broker SPO Partners II, L.P. 8/14/09 Sell 2,412 19.90 Open Market/Broker SPO Partners II, L.P. 8/14/09 Sell 198 19.91 Open Market/Broker

Page 26 of 41 pages SCHEDULE I TO SCHEDULE 13D DATE OF NUMBER OF PRICE PER WHERE/HOW TRANSACTION REPORTING PERSON TRANSACTION TYPE SHARES SHARE $ EFFECTED - ---------------------------------------- ----------- ---- --------- --------- ---------------------- SPO Partners II, L.P. 8/14/09 Sell 691 19.92 Open Market/Broker SPO Partners II, L.P. 8/14/09 Sell 2,754 19.93 Open Market/Broker SPO Partners II, L.P. 8/14/09 Sell 1,670 19.94 Open Market/Broker SPO Partners II, L.P. 8/14/09 Sell 1,292 19.95 Open Market/Broker SPO Partners II, L.P. 8/14/09 Sell 2,459 19.96 Open Market/Broker SPO Partners II, L.P. 8/14/09 Sell 2,471 19.97 Open Market/Broker SPO Partners II, L.P. 8/14/09 Sell 1,622 19.98 Open Market/Broker SPO Partners II, L.P. 8/14/09 Sell 1,575 19.99 Open Market/Broker SPO Partners II, L.P. 8/14/09 Sell 5,034 20.00 Open Market/Broker SPO Partners II, L.P. 8/14/09 Sell 2,227 20.01 Open Market/Broker SPO Partners II, L.P. 8/14/09 Sell 2,865 20.02 Open Market/Broker SPO Partners II, L.P. 8/14/09 Sell 1,086 20.03 Open Market/Broker SPO Partners II, L.P. 8/14/09 Sell 493 20.04 Open Market/Broker SPO Partners II, L.P. 8/14/09 Sell 100 20.05 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/14/09 Sell 27 19.75 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/14/09 Sell 17 19.76 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/14/09 Sell 8 19.77 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/14/09 Sell 11 19.78 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/14/09 Sell 12 19.79 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/14/09 Sell 14 19.80 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/14/09 Sell 11 19.81 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/14/09 Sell 4 19.82 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/14/09 Sell 5 19.83 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/14/09 Sell 5 19.84 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/14/09 Sell 7 19.85 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/14/09 Sell 6 19.86 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/14/09 Sell 8 19.87 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/14/09 Sell 3 19.88 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/14/09 Sell 4 19.89 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/14/09 Sell 5 19.90 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/14/09 Sell 1 19.92 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/14/09 Sell 6 19.93 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/14/09 Sell 3 19.94 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/14/09 Sell 3 19.95 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/14/09 Sell 5 19.96 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/14/09 Sell 5 19.97 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/14/09 Sell 3 19.98 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/14/09 Sell 3 19.99 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/14/09 Sell 10 20.00 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/14/09 Sell 5 20.01 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/14/09 Sell 6 20.02 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/14/09 Sell 2 20.03 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/14/09 Sell 1 20.04 Open Market/Broker

Page 27 of 41 pages SCHEDULE I TO SCHEDULE 13D DATE OF NUMBER OF PRICE PER WHERE/HOW TRANSACTION REPORTING PERSON TRANSACTION TYPE SHARES SHARE $ EFFECTED - ---------------------------------------- ----------- ---- --------- --------- ---------------------- William E. Oberndorf IRA 8/14/09 Sell 148 19.75 Open Market/Broker William E. Oberndorf IRA 8/14/09 Sell 93 19.76 Open Market/Broker William E. Oberndorf IRA 8/14/09 Sell 45 19.77 Open Market/Broker William E. Oberndorf IRA 8/14/09 Sell 61 19.78 Open Market/Broker William E. Oberndorf IRA 8/14/09 Sell 69 19.79 Open Market/Broker William E. Oberndorf IRA 8/14/09 Sell 75 19.80 Open Market/Broker William E. Oberndorf IRA 8/14/09 Sell 62 19.81 Open Market/Broker William E. Oberndorf IRA 8/14/09 Sell 20 19.82 Open Market/Broker William E. Oberndorf IRA 8/14/09 Sell 29 19.83 Open Market/Broker William E. Oberndorf IRA 8/14/09 Sell 26 19.84 Open Market/Broker William E. Oberndorf IRA 8/14/09 Sell 37 19.85 Open Market/Broker William E. Oberndorf IRA 8/14/09 Sell 33 19.86 Open Market/Broker William E. Oberndorf IRA 8/14/09 Sell 41 19.87 Open Market/Broker William E. Oberndorf IRA 8/14/09 Sell 14 19.88 Open Market/Broker William E. Oberndorf IRA 8/14/09 Sell 24 19.89 Open Market/Broker William E. Oberndorf IRA 8/14/09 Sell 27 19.90 Open Market/Broker William E. Oberndorf IRA 8/14/09 Sell 2 19.91 Open Market/Broker William E. Oberndorf IRA 8/14/09 Sell 8 19.92 Open Market/Broker William E. Oberndorf IRA 8/14/09 Sell 31 19.93 Open Market/Broker William E. Oberndorf IRA 8/14/09 Sell 19 19.94 Open Market/Broker William E. Oberndorf IRA 8/14/09 Sell 14 19.95 Open Market/Broker William E. Oberndorf IRA 8/14/09 Sell 27 19.96 Open Market/Broker William E. Oberndorf IRA 8/14/09 Sell 28 19.97 Open Market/Broker William E. Oberndorf IRA 8/14/09 Sell 18 19.98 Open Market/Broker William E. Oberndorf IRA 8/14/09 Sell 18 19.99 Open Market/Broker William E. Oberndorf IRA 8/14/09 Sell 56 20.00 Open Market/Broker William E. Oberndorf IRA 8/14/09 Sell 25 20.01 Open Market/Broker William E. Oberndorf IRA 8/14/09 Sell 32 20.02 Open Market/Broker William E. Oberndorf IRA 8/14/09 Sell 12 20.03 Open Market/Broker William E. Oberndorf IRA 8/14/09 Sell 6 20.04 Open Market/Broker SPO Partners II, L.P. 8/17/09 Sell 797 19.35 Open Market/Broker SPO Partners II, L.P. 8/17/09 Sell 686 19.36 Open Market/Broker SPO Partners II, L.P. 8/17/09 Sell 395 19.37 Open Market/Broker SPO Partners II, L.P. 8/17/09 Sell 1,284 19.38 Open Market/Broker SPO Partners II, L.P. 8/17/09 Sell 1,580 19.39 Open Market/Broker SPO Partners II, L.P. 8/17/09 Sell 2,182 19.40 Open Market/Broker SPO Partners II, L.P. 8/17/09 Sell 5,177 19.41 Open Market/Broker SPO Partners II, L.P. 8/17/09 Sell 2,574 19.42 Open Market/Broker SPO Partners II, L.P. 8/17/09 Sell 3,898 19.43 Open Market/Broker SPO Partners II, L.P. 8/17/09 Sell 6,904 19.44 Open Market/Broker SPO Partners II, L.P. 8/17/09 Sell 6,269 19.45 Open Market/Broker SPO Partners II, L.P. 8/17/09 Sell 4,306 19.46 Open Market/Broker SPO Partners II, L.P. 8/17/09 Sell 4,938 19.47 Open Market/Broker

Page 28 of 41 pages SCHEDULE I TO SCHEDULE 13D DATE OF NUMBER OF PRICE PER WHERE/HOW TRANSACTION REPORTING PERSON TRANSACTION TYPE SHARES SHARE $ EFFECTED - ---------------------------------------- ----------- ---- --------- --------- ---------------------- SPO Partners II, L.P. 8/17/09 Sell 2,932 19.48 Open Market/Broker SPO Partners II, L.P. 8/17/09 Sell 1,807 19.49 Open Market/Broker SPO Partners II, L.P. 8/17/09 Sell 6,686 19.50 Open Market/Broker SPO Partners II, L.P. 8/17/09 Sell 987 19.51 Open Market/Broker SPO Partners II, L.P. 8/17/09 Sell 2,568 19.52 Open Market/Broker SPO Partners II, L.P. 8/17/09 Sell 232 19.53 Open Market/Broker SPO Partners II, L.P. 8/17/09 Sell 98 19.55 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/17/09 Sell 1 19.35 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/17/09 Sell 1 19.36 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/17/09 Sell 1 19.37 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/17/09 Sell 2 19.38 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/17/09 Sell 3 19.39 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/17/09 Sell 4 19.40 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/17/09 Sell 9 19.41 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/17/09 Sell 5 19.42 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/17/09 Sell 7 19.43 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/17/09 Sell 12 19.44 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/17/09 Sell 11 19.45 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/17/09 Sell 8 19.46 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/17/09 Sell 9 19.47 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/17/09 Sell 5 19.48 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/17/09 Sell 3 19.49 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/17/09 Sell 12 19.50 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/17/09 Sell 2 19.51 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/17/09 Sell 5 19.52 Open Market/Broker William E. Oberndorf IRA 8/17/09 Sell 8 19.35 Open Market/Broker William E. Oberndorf IRA 8/17/09 Sell 7 19.36 Open Market/Broker William E. Oberndorf IRA 8/17/09 Sell 4 19.37 Open Market/Broker William E. Oberndorf IRA 8/17/09 Sell 14 19.38 Open Market/Broker William E. Oberndorf IRA 8/17/09 Sell 17 19.39 Open Market/Broker William E. Oberndorf IRA 8/17/09 Sell 23 19.40 Open Market/Broker William E. Oberndorf IRA 8/17/09 Sell 55 19.41 Open Market/Broker William E. Oberndorf IRA 8/17/09 Sell 27 19.42 Open Market/Broker William E. Oberndorf IRA 8/17/09 Sell 42 19.43 Open Market/Broker William E. Oberndorf IRA 8/17/09 Sell 74 19.44 Open Market/Broker William E. Oberndorf IRA 8/17/09 Sell 67 19.45 Open Market/Broker William E. Oberndorf IRA 8/17/09 Sell 46 19.46 Open Market/Broker William E. Oberndorf IRA 8/17/09 Sell 53 19.47 Open Market/Broker William E. Oberndorf IRA 8/17/09 Sell 31 19.48 Open Market/Broker William E. Oberndorf IRA 8/17/09 Sell 19 19.49 Open Market/Broker William E. Oberndorf IRA 8/17/09 Sell 71 19.50 Open Market/Broker William E. Oberndorf IRA 8/17/09 Sell 11 19.51 Open Market/Broker William E. Oberndorf IRA 8/17/09 Sell 27 19.52 Open Market/Broker

Page 29 of 41 pages SCHEDULE I TO SCHEDULE 13D DATE OF NUMBER OF PRICE PER WHERE/HOW TRANSACTION REPORTING PERSON TRANSACTION TYPE SHARES SHARE $ EFFECTED - ---------------------------------------- ----------- ---- --------- --------- ---------------------- William E. Oberndorf IRA 8/17/09 Sell 2 19.53 Open Market/Broker William E. Oberndorf IRA 8/17/09 Sell 2 19.55 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 986 19.27 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 690 19.29 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 122 19.30 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 394 19.32 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 296 19.33 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 2,536 19.34 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 1,706 19.35 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 197 19.36 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 888 19.37 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 1,380 19.38 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 667 19.39 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 394 19.40 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 394 19.41 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 99 19.42 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 394 19.43 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 197 19.44 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 394 19.45 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 394 19.46 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 99 19.47 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 334 19.48 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 356 19.49 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 1,183 19.50 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 107 19.51 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 394 19.52 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 91 19.53 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 37 19.54 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 2,073 19.56 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 226 19.57 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 491 19.58 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 99 19.59 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 417 19.60 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 713 19.61 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 591 19.62 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 591 19.63 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 1,395 19.64 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 725 19.65 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 332 19.66 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 197 19.67 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 591 19.68 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 99 19.69 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 296 19.70 Open Market/Broker

Page 30 of 41 pages SCHEDULE I TO SCHEDULE 13D DATE OF NUMBER OF PRICE PER WHERE/HOW TRANSACTION REPORTING PERSON TRANSACTION TYPE SHARES SHARE $ EFFECTED - ---------------------------------------- ----------- ---- --------- --------- ---------------------- SPO Partners II, L.P. 8/18/09 Sell 986 19.71 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 296 19.72 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 197 19.74 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 789 19.75 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 99 19.76 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 99 19.79 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 99 19.80 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 690 19.81 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 3,945 19.82 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 394 19.83 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 1,380 19.84 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 6,359 19.85 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 2,454 19.86 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 3,271 19.87 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 3,461 19.88 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 3,687 19.89 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 8,876 19.90 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 5,030 19.91 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 99 19.92 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 690 19.93 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 591 19.94 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 493 19.95 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 1,972 19.97 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 788 19.98 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 4,139 19.99 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 7,906 20.00 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 1,677 20.01 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 1,765 20.02 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 4,044 20.03 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 2,708 20.04 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 2,778 20.05 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 394 20.06 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 789 20.07 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 62 20.08 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 789 20.09 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 591 20.10 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 2,663 20.11 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 1,972 20.12 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 2,860 20.13 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 4,037 20.14 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 5,011 20.15 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 1,479 20.16 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 8,383 20.17 Open Market/Broker

Page 31 of 41 pages SCHEDULE I TO SCHEDULE 13D DATE OF NUMBER OF PRICE PER WHERE/HOW TRANSACTION REPORTING PERSON TRANSACTION TYPE SHARES SHARE $ EFFECTED - ---------------------------------------- ----------- ---- --------- --------- ---------------------- SPO Partners II, L.P. 8/18/09 Sell 9,492 20.18 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 8,813 20.19 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 3,345 20.20 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 6,972 20.21 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 3,431 20.22 Open Market/Broker SPO Partners II, L.P. 8/18/09 Sell 1,290 20.23 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 3 19.27 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 2 19.29 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 1 19.32 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 1 19.33 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 6 19.34 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 4 19.35 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 1 19.36 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 2 19.37 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 4 19.38 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 2 19.39 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 1 19.40 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 1 19.41 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 1 19.43 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 1 19.44 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 1 19.45 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 1 19.46 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 1 19.48 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 1 19.49 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 3 19.50 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 1 19.52 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 5 19.56 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 1 19.57 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 1 19.58 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 1 19.60 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 2 19.61 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 2 19.62 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 2 19.63 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 4 19.64 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 2 19.65 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 1 19.66 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 1 19.67 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 2 19.68 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 1 19.70 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 3 19.71 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 1 19.72 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 1 19.74 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 2 19.75 Open Market/Broker

Page 32 of 41 pages SCHEDULE I TO SCHEDULE 13D DATE OF NUMBER OF PRICE PER WHERE/HOW TRANSACTION REPORTING PERSON TRANSACTION TYPE SHARES SHARE $ EFFECTED - ---------------------------------------- ----------- ---- --------- --------- ---------------------- The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 2 19.81 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 10 19.82 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 1 19.83 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 4 19.84 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 16 19.85 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 6 19.86 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 8 19.87 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 9 19.88 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 9 19.89 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 23 19.90 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 13 19.91 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 2 19.93 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 2 19.94 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 1 19.95 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 5 19.97 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 2 19.98 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 10 19.99 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 20 20.00 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 4 20.01 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 4 20.02 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 10 20.03 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 7 20.04 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 7 20.05 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 1 20.06 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 2 20.07 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 2 20.09 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 2 20.10 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 7 20.11 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 5 20.12 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 7 20.13 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 10 20.14 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 13 20.15 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 4 20.16 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 21 20.17 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 24 20.18 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 22 20.19 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 8 20.20 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 18 20.21 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/18/09 Sell 9 20.22 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 11 19.27 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 8 19.29 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 1 19.30 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 5 19.32 Open Market/Broker

Page 33 of 41 pages SCHEDULE I TO SCHEDULE 13D DATE OF NUMBER OF PRICE PER WHERE/HOW TRANSACTION REPORTING PERSON TRANSACTION TYPE SHARES SHARE $ EFFECTED - ---------------------------------------- ----------- ---- --------- --------- ---------------------- William E. Oberndorf IRA 8/18/09 Sell 3 19.33 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 29 19.34 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 19 19.35 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 2 19.36 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 10 19.37 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 16 19.38 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 8 19.39 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 5 19.40 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 5 19.41 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 1 19.42 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 5 19.43 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 2 19.44 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 5 19.45 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 5 19.46 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 1 19.47 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 4 19.48 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 4 19.49 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 14 19.50 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 1 19.51 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 5 19.52 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 1 19.53 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 24 19.56 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 3 19.57 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 6 19.58 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 1 19.59 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 5 19.60 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 8 19.61 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 7 19.62 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 7 19.63 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 16 19.64 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 8 19.65 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 4 19.66 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 2 19.67 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 7 19.68 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 1 19.69 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 3 19.70 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 11 19.71 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 3 19.72 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 2 19.74 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 9 19.75 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 1 19.76 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 1 19.79 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 1 19.80 Open Market/Broker

Page 34 of 41 pages SCHEDULE I TO SCHEDULE 13D DATE OF NUMBER OF PRICE PER WHERE/HOW TRANSACTION REPORTING PERSON TRANSACTION TYPE SHARES SHARE $ EFFECTED - ---------------------------------------- ----------- ---- --------- --------- ---------------------- William E. Oberndorf IRA 8/18/09 Sell 8 19.81 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 45 19.82 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 5 19.83 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 16 19.84 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 73 19.85 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 28 19.86 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 37 19.87 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 40 19.88 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 42 19.89 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 101 19.90 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 57 19.91 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 1 19.92 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 8 19.93 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 7 19.94 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 6 19.95 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 23 19.97 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 9 19.98 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 47 19.99 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 90 20.00 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 19 20.01 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 20 20.02 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 46 20.03 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 31 20.04 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 32 20.05 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 5 20.06 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 9 20.07 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 1 20.08 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 9 20.09 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 7 20.10 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 30 20.11 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 23 20.12 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 33 20.13 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 46 20.14 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 57 20.15 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 17 20.16 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 96 20.17 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 108 20.18 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 101 20.19 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 38 20.20 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 80 20.21 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 39 20.22 Open Market/Broker William E. Oberndorf IRA 8/18/09 Sell 10 20.23 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 198 19.51 Open Market/Broker

Page 35 of 41 pages SCHEDULE I TO SCHEDULE 13D DATE OF NUMBER OF PRICE PER WHERE/HOW TRANSACTION REPORTING PERSON TRANSACTION TYPE SHARES SHARE $ EFFECTED - ---------------------------------------- ----------- ---- --------- --------- ---------------------- SPO Partners II, L.P. 8/19/09 Sell 1,479 19.53 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 394 19.54 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 493 19.55 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 198 19.60 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 198 19.61 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 196 19.63 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 790 19.64 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 1,085 19.65 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 99 19.66 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 592 19.67 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 986 19.68 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 503 19.69 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 495 19.70 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 790 19.71 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 376 19.73 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 9 19.74 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 198 19.75 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 198 19.76 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 1,378 19.77 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 201 19.78 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 790 19.79 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 790 19.80 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 1,875 19.81 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 790 19.82 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 2,170 19.83 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 887 19.84 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 790 19.85 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 198 19.86 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 437 19.88 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 56 19.89 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 147 19.90 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 717 19.91 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 1,499 19.92 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 1,087 19.93 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 491 19.94 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 760 19.95 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 3,846 19.96 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 693 19.97 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 208 19.98 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 592 19.99 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 116 20.00 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 785 20.01 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 409 20.02 Open Market/Broker

Page 36 of 41 pages SCHEDULE I TO SCHEDULE 13D DATE OF NUMBER OF PRICE PER WHERE/HOW TRANSACTION REPORTING PERSON TRANSACTION TYPE SHARES SHARE $ EFFECTED - ---------------------------------------- ----------- ---- --------- --------- ---------------------- SPO Partners II, L.P. 8/19/09 Sell 100 20.04 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 296 20.05 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 1,761 20.06 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 601 20.07 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 198 20.08 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 1,381 20.09 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 198 20.10 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 1,479 20.11 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 1,712 20.12 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 2,071 20.13 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 2,170 20.14 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 6,057 20.15 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 5,439 20.16 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 4,158 20.17 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 5,333 20.18 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 2,525 20.19 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 9,204 20.20 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 1,997 20.21 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 4,316 20.22 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 516 20.23 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 1,774 20.24 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 270 20.25 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 822 20.26 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 1,778 20.27 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 924 20.28 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 2,918 20.29 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 1,156 20.30 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 592 20.31 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 1,749 20.32 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 521 20.33 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 1,467 20.34 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 1,280 20.35 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 2,286 20.36 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 2,577 20.37 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 1,457 20.38 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 795 20.39 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 525 20.40 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 99 20.41 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 394 20.42 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 799 20.43 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 254 20.44 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 592 20.46 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 206 20.47 Open Market/Broker

Page 37 of 41 pages SCHEDULE I TO SCHEDULE 13D DATE OF NUMBER OF PRICE PER WHERE/HOW TRANSACTION REPORTING PERSON TRANSACTION TYPE SHARES SHARE $ EFFECTED - ---------------------------------------- ----------- ---- --------- --------- ---------------------- SPO Partners II, L.P. 8/19/09 Sell 1,099 20.48 Open Market/Broker SPO Partners II, L.P. 8/19/09 Sell 665 20.49 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 3 19.53 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 1 19.54 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 1 19.55 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 1 19.64 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 2 19.65 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 1 19.67 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 2 19.68 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 1 19.69 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 1 19.70 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 1 19.71 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 1 19.73 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 3 19.77 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 1 19.79 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 1 19.80 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 3 19.81 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 1 19.82 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 4 19.83 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 2 19.84 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 1 19.85 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 1 19.88 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 1 19.91 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 3 19.92 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 2 19.93 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 1 19.94 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 1 19.95 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 7 19.96 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 1 19.97 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 1 19.99 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 1 20.01 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 1 20.02 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 1 20.05 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 3 20.06 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 1 20.07 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 3 20.09 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 3 20.11 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 3 20.12 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 4 20.13 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 4 20.14 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 11 20.15 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 10 20.16 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 8 20.17 Open Market/Broker

Page 38 of 41 pages SCHEDULE I TO SCHEDULE 13D DATE OF NUMBER OF PRICE PER WHERE/HOW TRANSACTION REPORTING PERSON TRANSACTION TYPE SHARES SHARE $ EFFECTED - ---------------------------------------- ----------- ---- --------- --------- ---------------------- The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 10 20.18 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 5 20.19 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 17 20.20 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 4 20.21 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 8 20.22 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 1 20.23 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 3 20.24 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 2 20.26 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 3 20.27 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 2 20.28 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 5 20.29 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 2 20.30 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 1 20.31 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 3 20.32 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 1 20.33 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 3 20.34 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 2 20.35 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 4 20.36 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 5 20.37 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 3 20.38 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 1 20.39 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 1 20.40 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 1 20.42 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 1 20.43 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 1 20.46 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 2 20.48 Open Market/Broker The Elizabeth R. and William J. Patterson Foundation 8/19/09 Sell 7 20.49 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 2 19.51 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 18 19.53 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 5 19.54 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 6 19.55 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 2 19.60 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 2 19.61 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 2 19.63 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 9 19.64 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 13 19.65 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 1 19.66 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 7 19.67 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 12 19.68 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 6 19.69 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 6 19.70 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 9 19.71 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 4 19.73 Open Market/Broker

Page 39 of 41 pages SCHEDULE I TO SCHEDULE 13D DATE OF NUMBER OF PRICE PER WHERE/HOW TRANSACTION REPORTING PERSON TRANSACTION TYPE SHARES SHARE $ EFFECTED - ---------------------------------------- ----------- ---- --------- --------- ---------------------- William E. Oberndorf IRA 8/19/09 Sell 2 19.75 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 2 19.76 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 16 19.77 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 2 19.78 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 9 19.79 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 9 19.80 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 22 19.81 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 9 19.82 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 26 19.83 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 11 19.84 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 9 19.85 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 2 19.86 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 5 19.88 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 1 19.89 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 2 19.90 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 9 19.91 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 18 19.92 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 13 19.93 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 6 19.94 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 9 19.95 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 46 19.96 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 8 19.97 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 2 19.98 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 7 19.99 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 1 20.00 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 9 20.01 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 5 20.02 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 1 20.04 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 4 20.05 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 21 20.06 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 7 20.07 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 2 20.08 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 16 20.09 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 2 20.10 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 18 20.11 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 20 20.12 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 25 20.13 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 26 20.14 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 72 20.15 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 65 20.16 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 49 20.17 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 63 20.18 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 30 20.19 Open Market/Broker

Page 40 of 41 pages SCHEDULE I TO SCHEDULE 13D DATE OF NUMBER OF PRICE PER WHERE/HOW TRANSACTION REPORTING PERSON TRANSACTION TYPE SHARES SHARE $ EFFECTED - ---------------------------------------- ----------- ---- --------- --------- ---------------------- William E. Oberndorf IRA 8/19/09 Sell 109 20.20 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 24 20.21 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 51 20.22 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 6 20.23 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 21 20.24 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 3 20.25 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 10 20.26 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 21 20.27 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 11 20.28 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 35 20.29 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 14 20.30 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 7 20.31 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 21 20.32 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 6 20.33 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 17 20.34 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 15 20.35 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 27 20.36 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 31 20.37 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 17 20.38 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 9 20.39 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 6 20.40 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 1 20.41 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 5 20.42 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 9 20.43 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 3 20.44 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 7 20.46 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 2 20.47 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 13 20.48 Open Market/Broker William E. Oberndorf IRA 8/19/09 Sell 14 20.49 Open Market/Broker

Page 41 of 41 pages EXHIBIT INDEX EXHIBIT DOCUMENT DESCRIPTION - ------- ------------------------------------ A Joint Filing Agreement

                                    EXHIBIT A

         Pursuant to Rule 13d-1(k) of Regulation 13D-G of the General Rules and
Regulations of the Securities and Exchange Commission under the Securities
Exchange Act of 1934, as amended, the undersigned agrees that the statement to
which this Exhibit is attached is filed on behalf of each of them in the
capacities set forth below.


Dated: August 21, 2009                  By:       /s/ Kim M. Silva
                                               --------------------------------
                                                   Kim M. Silva

                                           Attorney-in-Fact for:

                                           SPO PARTNERS II, L.P.(1)
                                           SPO ADVISORY PARTNERS, L.P.(1)
                                           SPO ADVISORY CORP.(1)
                                           JOHN H. SCULLY(1)
                                           WILLIAM E. OBERNDORF(1)
                                           WILLIAM J. PATTERSON(1)
                                           EDWARD H. MCDERMOTT(1)
                                           WILLIAM AND SUSAN OBERNDORF TRUST,
                                              DATED 10/19/98 (1)
                                           OBERNDORF FAMILY PARTNERS (1)
                                           THE ELIZABETH R. & WILLIAM J.
                                             PATTERSON FOUNDATION (1)
                                           IAN R. MCGUIRE (1)
                                           BETTY JANE WEIMER (1)

                                           (1) A Power of Attorney
                                           authorizing Kim M. Silva to
                                           act on behalf of this
                                           person or entity has been previously
                                           filed with the Securities and
                                           Exchange Commission.