SEC Filing | Cabot Corporation

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SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 13D Under the Securities Exchange Act of 1934 (Amendment No. 12)* 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 10, 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 39 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 3,450,350 (1) ------------------------------------------------------ Number Of Shares 8. SHARED VOTING POWER Beneficially Owned By -0- Each Reporting Person ------------------------------------------------------ With 9. SOLE DISPOSITIVE POWER 3,450,350 (1) ------------------------------------------------------ 10. SHARED DISPOSITIVE POWER -0- - -------------------------------------------------------------------------------- 11. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 3,450,350 - -------------------------------------------------------------------------------- 12. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES [_] - -------------------------------------------------------------------------------- 13. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 5.3% - -------------------------------------------------------------------------------- 14. TYPE OF REPORTING PERSON PN - -------------------------------------------------------------------------------- (1) Power is exercised through its sole general partner, SPO Advisory Partners, L.P.

Page 3 of 39 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 3,450,350 (1)(2) ------------------------------------------------------ Number Of Shares 8. SHARED VOTING POWER Beneficially Owned By -0- Each Reporting Person ------------------------------------------------------ With 9. SOLE DISPOSITIVE POWER 3,450,350 (1)(2) ------------------------------------------------------ 10. SHARED DISPOSITIVE POWER -0- - -------------------------------------------------------------------------------- 11. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 3,450,350 - -------------------------------------------------------------------------------- 12. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES [_] - -------------------------------------------------------------------------------- 13. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 5.3% - -------------------------------------------------------------------------------- 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 39 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 3,450,350 (1)(2) ------------------------------------------------------ Number Of Shares 8. SHARED VOTING POWER Beneficially Owned By -0- Each Reporting Person ------------------------------------------------------ With 9. SOLE DISPOSITIVE POWER 3,450,350 (1)(2) ------------------------------------------------------ 10. SHARED DISPOSITIVE POWER -0- - -------------------------------------------------------------------------------- 11. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 3,450,350 - -------------------------------------------------------------------------------- 12. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES [_] - -------------------------------------------------------------------------------- 13. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 5.3% - -------------------------------------------------------------------------------- 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 3,450,350 of 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 39 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 3,450,350 (1) Each Reporting Person ------------------------------------------------------ With 9. SOLE DISPOSITIVE POWER -0- ------------------------------------------------------ 10. SHARED DISPOSITIVE POWER 3,450,350 (1) - -------------------------------------------------------------------------------- 11. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 3,450,350 - -------------------------------------------------------------------------------- 12. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES [_] - -------------------------------------------------------------------------------- 13. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 5.3% - -------------------------------------------------------------------------------- 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 39 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 149,000 (1) ------------------------------------------------------ Number Of Shares 8. SHARED VOTING POWER Beneficially Owned By 3,784,000 (2) Each Reporting Person ------------------------------------------------------ With 9. SOLE DISPOSITIVE POWER 149,000 (1) ------------------------------------------------------ 10. SHARED DISPOSITIVE POWER 3,784,000 (2) - -------------------------------------------------------------------------------- 11. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 3,933,000 - -------------------------------------------------------------------------------- 12. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES [_] - -------------------------------------------------------------------------------- 13. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 6.0% - -------------------------------------------------------------------------------- 14. TYPE OF REPORTING PERSON IN - -------------------------------------------------------------------------------- (1) Of these shares, 39,000 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, 3,450,350 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 39 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 39 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 39 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 3,458,050 (1) Each Reporting Person ------------------------------------------------------ With 9. SOLE DISPOSITIVE POWER -0- ------------------------------------------------------ 10. SHARED DISPOSITIVE POWER 3,458,050 (1) - -------------------------------------------------------------------------------- 11. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 3,458,050 - -------------------------------------------------------------------------------- 12. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES [_] - -------------------------------------------------------------------------------- 13. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 5.3% - -------------------------------------------------------------------------------- 14. TYPE OF REPORTING PERSON IN - -------------------------------------------------------------------------------- (1) Of these shares, 3,450,350 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 7,700 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 39 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 7,700 (1) ------------------------------------------------------ Number Of Shares 8. SHARED VOTING POWER Beneficially Owned By -0- Each Reporting Person ------------------------------------------------------ With 9. SOLE DISPOSITIVE POWER 7,700 (1) ------------------------------------------------------ 10. SHARED DISPOSITIVE POWER -0- - -------------------------------------------------------------------------------- 11. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 7,700 - -------------------------------------------------------------------------------- 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 39 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 3,450,350 (1) Each Reporting Person ------------------------------------------------------ With 9. SOLE DISPOSITIVE POWER -0- ------------------------------------------------------ 10. SHARED DISPOSITIVE POWER 3,450,350 (1) - -------------------------------------------------------------------------------- 11. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 3,450,350 - -------------------------------------------------------------------------------- 12. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES [_] - -------------------------------------------------------------------------------- 13. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 5.3% - -------------------------------------------------------------------------------- 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 39 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 39 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 39 pages This Amendment No. 12 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 and August 5, 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 39 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 $206,787,558 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) $ 4,199,953 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 $ 476,291 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 3,450,350 Shares, which constitutes approximately 5.3% 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 3,450,350 Shares, which constitutes approximately 5.3% 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 3,450,350 Shares in the aggregate, which constitutes approximately 5.3% 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 3,450,350 Shares, which constitutes approximately 5.3% 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 3,933,000 Shares in the aggregate, which constitutes approximately 6.0% of the outstanding Shares.

Page 16 of 39 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 3,458,050 Shares, which constitutes approximately 5.3% 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 3,450,350 Shares, which constitutes approximately 5.3% 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 7,700, 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 3,450,350 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 3,450,350 Shares.

Page 17 of 39 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 3,450,350 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 3,450,350 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 3,450,350 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 39,000 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 3,450,350 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 7,700 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 3,450,350 Shares held by SPO.

Page 18 of 39 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 7,700 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) Not applicable. 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 39 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 12, 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 39 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. 08/05/09 Sell 99 19.07 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 198 19.08 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 99 19.09 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 296 19.10 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 1,184 19.11 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 1,086 19.12 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 2,369 19.13 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 2,270 19.14 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 3,568 19.15 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 8,371 19.16 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 6,747 19.17 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 6,563 19.18 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 30,518 19.19 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 100,748 19.20 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 14,204 19.21 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 11,921 19.22 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 18,137 19.23 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 5,818 19.24 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 3,978 19.25 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 2,763 19.26 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 2,565 19.27 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 592 19.28 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 12,631 19.29 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 1,480 19.30 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 1,382 19.31 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 789 19.32 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 1,382 19.33 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 1,382 19.34 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 296 19.35 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 395 19.36 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 690 19.37 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 493 19.38 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 987 19.39 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 1,283 19.40 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 493 19.41 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 296 19.42 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 198 19.43 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 198 19.44 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 198 19.47 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 493 19.50 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 99 19.52 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 99 19.53 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 99 19.56 Open Market/Broker

Page 21 of 39 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. 08/05/09 Sell 296 19.57 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 99 19.58 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 99 19.59 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 395 19.62 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 99 19.63 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 198 19.64 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 296 19.65 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 198 19.66 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 198 19.67 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 493 19.68 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 99 19.69 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 493 19.70 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 493 19.71 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 395 19.72 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 296 19.73 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 99 19.74 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 493 19.75 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 395 19.76 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 592 19.77 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 99 19.78 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 296 19.79 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 99 19.80 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 69 19.81 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 198 19.82 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 99 19.83 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 99 19.85 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 198 19.86 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 592 19.87 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 326 19.88 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 296 19.89 Open Market/Broker SPO Partners II, L.P. 08/05/09 Sell 46 19.90 Open Market/Broker The Elizabeth R. and William J. 08/05/09 Sell 1 19.10 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/05/09 Sell 3 19.11 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/05/09 Sell 3 19.12 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/05/09 Sell 6 19.13 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/05/09 Sell 5 19.14 Open Market/Broker Patterson Foundation

Page 22 of 39 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. 08/05/09 Sell 8 19.15 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/05/09 Sell 19 19.16 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/05/09 Sell 16 19.17 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/05/09 Sell 15 19.18 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/05/09 Sell 71 19.19 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/05/09 Sell 235 19.20 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/05/09 Sell 33 19.21 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/05/09 Sell 28 19.22 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/05/09 Sell 42 19.23 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/05/09 Sell 14 19.24 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/05/09 Sell 9 19.25 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/05/09 Sell 6 19.26 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/05/09 Sell 6 19.27 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/05/09 Sell 1 19.28 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/05/09 Sell 29 19.29 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/05/09 Sell 3 19.30 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/05/09 Sell 3 19.31 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/05/09 Sell 2 19.32 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/05/09 Sell 3 19.33 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/05/09 Sell 3 19.34 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/05/09 Sell 1 19.35 Open Market/Broker Patterson Foundation

Page 23 of 39 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. 08/05/09 Sell 1 19.36 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/05/09 Sell 2 19.37 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/05/09 Sell 1 19.38 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/05/09 Sell 2 19.39 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/05/09 Sell 3 19.40 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/05/09 Sell 1 19.41 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/05/09 Sell 1 19.42 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/05/09 Sell 1 19.50 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/05/09 Sell 1 19.57 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/05/09 Sell 1 19.62 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/05/09 Sell 1 19.65 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/05/09 Sell 1 19.68 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/05/09 Sell 1 19.70 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/05/09 Sell 1 19.71 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/05/09 Sell 1 19.72 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/05/09 Sell 1 19.73 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/05/09 Sell 1 19.75 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/05/09 Sell 1 19.76 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/05/09 Sell 1 19.77 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/05/09 Sell 1 19.79 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/05/09 Sell 1 19.87 Open Market/Broker Patterson Foundation

Page 24 of 39 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. 08/05/09 Sell 1 19.88 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/05/09 Sell 1 19.89 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/05/09 Sell 8 19.90 Open Market/Broker Patterson Foundation William E. Oberndorf IRA 08/05/09 Sell 1 19.07 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 2 19.08 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 1 19.09 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 3 19.10 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 13 19.11 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 12 19.12 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 27 19.13 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 26 19.14 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 40 19.15 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 94 19.16 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 76 19.17 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 74 19.18 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 344 19.19 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 1,134 19.20 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 160 19.21 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 134 19.22 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 204 19.23 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 65 19.24 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 45 19.25 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 31 19.26 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 29 19.27 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 7 19.28 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 142 19.29 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 17 19.30 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 16 19.31 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 9 19.32 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 16 19.33 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 16 19.34 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 3 19.35 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 4 19.36 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 8 19.37 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 6 19.38 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 11 19.39 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 14 19.40 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 6 19.41 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 3 19.42 Open Market/Broker

Page 25 of 39 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 08/05/09 Sell 2 19.43 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 2 19.44 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 2 19.47 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 6 19.50 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 1 19.52 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 1 19.53 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 1 19.56 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 3 19.57 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 1 19.58 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 1 19.59 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 4 19.62 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 1 19.63 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 2 19.64 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 3 19.65 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 2 19.66 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 2 19.67 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 6 19.68 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 1 19.69 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 6 19.70 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 6 19.71 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 4 19.72 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 3 19.73 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 1 19.74 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 6 19.75 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 4 19.76 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 7 19.77 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 1 19.78 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 3 19.79 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 1 19.80 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 1 19.81 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 2 19.82 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 1 19.83 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 1 19.85 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 2 19.86 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 7 19.87 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 4 19.88 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 3 19.89 Open Market/Broker William E. Oberndorf IRA 08/05/09 Sell 3 19.90 Open Market/Broker SPO Partners II, L.P. 08/06/09 Sell 887 19.10 Open Market/Broker SPO Partners II, L.P. 08/06/09 Sell 768 19.11 Open Market/Broker SPO Partners II, L.P. 08/06/09 Sell 789 19.12 Open Market/Broker SPO Partners II, L.P. 08/06/09 Sell 1,771 19.13 Open Market/Broker

Page 26 of 39 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. 08/06/09 Sell 1,391 19.14 Open Market/Broker SPO Partners II, L.P. 08/06/09 Sell 690 19.15 Open Market/Broker SPO Partners II, L.P. 08/06/09 Sell 888 19.16 Open Market/Broker SPO Partners II, L.P. 08/06/09 Sell 789 19.17 Open Market/Broker SPO Partners II, L.P. 08/06/09 Sell 690 19.18 Open Market/Broker SPO Partners II, L.P. 08/06/09 Sell 6,216 19.19 Open Market/Broker SPO Partners II, L.P. 08/06/09 Sell 8,757 19.20 Open Market/Broker SPO Partners II, L.P. 08/06/09 Sell 4,244 19.21 Open Market/Broker SPO Partners II, L.P. 08/06/09 Sell 1,548 19.22 Open Market/Broker SPO Partners II, L.P. 08/06/09 Sell 493 19.23 Open Market/Broker SPO Partners II, L.P. 08/06/09 Sell 99 19.24 Open Market/Broker SPO Partners II, L.P. 08/06/09 Sell 198 19.25 Open Market/Broker SPO Partners II, L.P. 08/06/09 Sell 99 19.26 Open Market/Broker SPO Partners II, L.P. 08/06/09 Sell 888 19.27 Open Market/Broker SPO Partners II, L.P. 08/06/09 Sell 1,184 19.28 Open Market/Broker SPO Partners II, L.P. 08/06/09 Sell 198 19.29 Open Market/Broker SPO Partners II, L.P. 08/06/09 Sell 1,776 19.30 Open Market/Broker SPO Partners II, L.P. 08/06/09 Sell 2,072 19.31 Open Market/Broker SPO Partners II, L.P. 08/06/09 Sell 987 19.32 Open Market/Broker SPO Partners II, L.P. 08/06/09 Sell 2,862 19.33 Open Market/Broker SPO Partners II, L.P. 08/06/09 Sell 760 19.34 Open Market/Broker SPO Partners II, L.P. 08/06/09 Sell 2,101 19.35 Open Market/Broker SPO Partners II, L.P. 08/06/09 Sell 1,382 19.36 Open Market/Broker SPO Partners II, L.P. 08/06/09 Sell 493 19.37 Open Market/Broker SPO Partners II, L.P. 08/06/09 Sell 493 19.38 Open Market/Broker SPO Partners II, L.P. 08/06/09 Sell 493 19.39 Open Market/Broker SPO Partners II, L.P. 08/06/09 Sell 2,763 19.40 Open Market/Broker SPO Partners II, L.P. 08/06/09 Sell 2,547 19.41 Open Market/Broker SPO Partners II, L.P. 08/06/09 Sell 494 19.42 Open Market/Broker SPO Partners II, L.P. 08/06/09 Sell 1,283 19.43 Open Market/Broker SPO Partners II, L.P. 08/06/09 Sell 2,565 19.44 Open Market/Broker SPO Partners II, L.P. 08/06/09 Sell 2,647 19.45 Open Market/Broker SPO Partners II, L.P. 08/06/09 Sell 2,072 19.46 Open Market/Broker SPO Partners II, L.P. 08/06/09 Sell 1,293 19.47 Open Market/Broker SPO Partners II, L.P. 08/06/09 Sell 1,366 19.48 Open Market/Broker SPO Partners II, L.P. 08/06/09 Sell 2,069 19.49 Open Market/Broker SPO Partners II, L.P. 08/06/09 Sell 296 19.50 Open Market/Broker SPO Partners II, L.P. 08/06/09 Sell 99 19.51 Open Market/Broker The Elizabeth R. and William J. 08/06/09 Sell 3 19.10 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/06/09 Sell 2 19.11 Open Market/Broker Patterson Foundation

Page 27 of 39 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. 08/06/09 Sell 2 19.12 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/06/09 Sell 5 19.13 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/06/09 Sell 4 19.14 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/06/09 Sell 2 19.15 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/06/09 Sell 3 19.16 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/06/09 Sell 2 19.17 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/06/09 Sell 2 19.18 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/06/09 Sell 19 19.19 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/06/09 Sell 27 19.20 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/06/09 Sell 13 19.21 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/06/09 Sell 5 19.22 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/06/09 Sell 2 19.23 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/06/09 Sell 1 19.25 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/06/09 Sell 3 19.27 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/06/09 Sell 4 19.28 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/06/09 Sell 1 19.29 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/06/09 Sell 5 19.30 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/06/09 Sell 6 19.31 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/06/09 Sell 3 19.32 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/06/09 Sell 9 19.33 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/06/09 Sell 2 19.34 Open Market/Broker Patterson Foundation

Page 28 of 39 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. 08/06/09 Sell 6 19.35 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/06/09 Sell 4 19.36 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/06/09 Sell 2 19.37 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/06/09 Sell 2 19.38 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/06/09 Sell 2 19.39 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/06/09 Sell 8 19.40 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/06/09 Sell 8 19.41 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/06/09 Sell 2 19.42 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/06/09 Sell 4 19.43 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/06/09 Sell 8 19.44 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/06/09 Sell 8 19.45 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/06/09 Sell 6 19.46 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/06/09 Sell 4 19.47 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/06/09 Sell 4 19.48 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/06/09 Sell 6 19.49 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/06/09 Sell 1 19.50 Open Market/Broker Patterson Foundation William E. Oberndorf IRA 08/06/09 Sell 9 19.10 Open Market/Broker William E. Oberndorf IRA 08/06/09 Sell 8 19.11 Open Market/Broker William E. Oberndorf IRA 08/06/09 Sell 8 19.12 Open Market/Broker William E. Oberndorf IRA 08/06/09 Sell 19 19.13 Open Market/Broker William E. Oberndorf IRA 08/06/09 Sell 15 19.14 Open Market/Broker William E. Oberndorf IRA 08/06/09 Sell 7 19.15 Open Market/Broker William E. Oberndorf IRA 08/06/09 Sell 9 19.16 Open Market/Broker William E. Oberndorf IRA 08/06/09 Sell 8 19.17 Open Market/Broker William E. Oberndorf IRA 08/06/09 Sell 7 19.18 Open Market/Broker William E. Oberndorf IRA 08/06/09 Sell 66 19.19 Open Market/Broker

Page 29 of 39 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 08/06/09 Sell 94 19.20 Open Market/Broker William E. Oberndorf IRA 08/06/09 Sell 45 19.21 Open Market/Broker William E. Oberndorf IRA 08/06/09 Sell 17 19.22 Open Market/Broker William E. Oberndorf IRA 08/06/09 Sell 5 19.23 Open Market/Broker William E. Oberndorf IRA 08/06/09 Sell 1 19.24 Open Market/Broker William E. Oberndorf IRA 08/06/09 Sell 2 19.25 Open Market/Broker William E. Oberndorf IRA 08/06/09 Sell 1 19.26 Open Market/Broker William E. Oberndorf IRA 08/06/09 Sell 9 19.27 Open Market/Broker William E. Oberndorf IRA 08/06/09 Sell 13 19.28 Open Market/Broker William E. Oberndorf IRA 08/06/09 Sell 2 19.29 Open Market/Broker William E. Oberndorf IRA 08/06/09 Sell 19 19.30 Open Market/Broker William E. Oberndorf IRA 08/06/09 Sell 22 19.31 Open Market/Broker William E. Oberndorf IRA 08/06/09 Sell 11 19.32 Open Market/Broker William E. Oberndorf IRA 08/06/09 Sell 31 19.33 Open Market/Broker William E. Oberndorf IRA 08/06/09 Sell 8 19.34 Open Market/Broker William E. Oberndorf IRA 08/06/09 Sell 22 19.35 Open Market/Broker William E. Oberndorf IRA 08/06/09 Sell 15 19.36 Open Market/Broker William E. Oberndorf IRA 08/06/09 Sell 5 19.37 Open Market/Broker William E. Oberndorf IRA 08/06/09 Sell 5 19.38 Open Market/Broker William E. Oberndorf IRA 08/06/09 Sell 5 19.39 Open Market/Broker William E. Oberndorf IRA 08/06/09 Sell 30 19.40 Open Market/Broker William E. Oberndorf IRA 08/06/09 Sell 27 19.41 Open Market/Broker William E. Oberndorf IRA 08/06/09 Sell 5 19.42 Open Market/Broker William E. Oberndorf IRA 08/06/09 Sell 14 19.43 Open Market/Broker William E. Oberndorf IRA 08/06/09 Sell 27 19.44 Open Market/Broker William E. Oberndorf IRA 08/06/09 Sell 28 19.45 Open Market/Broker William E. Oberndorf IRA 08/06/09 Sell 22 19.46 Open Market/Broker William E. Oberndorf IRA 08/06/09 Sell 14 19.47 Open Market/Broker William E. Oberndorf IRA 08/06/09 Sell 15 19.48 Open Market/Broker William E. Oberndorf IRA 08/06/09 Sell 22 19.49 Open Market/Broker William E. Oberndorf IRA 08/06/09 Sell 3 19.50 Open Market/Broker William E. Oberndorf IRA 08/06/09 Sell 5 19.51 Open Market/Broker SPO Partners II, L.P. 08/07/09 Sell 2,270 19.90 Open Market/Broker SPO Partners II, L.P. 08/07/09 Sell 2,565 19.91 Open Market/Broker SPO Partners II, L.P. 08/07/09 Sell 2,128 19.92 Open Market/Broker SPO Partners II, L.P. 08/07/09 Sell 621 19.93 Open Market/Broker SPO Partners II, L.P. 08/07/09 Sell 2,369 19.94 Open Market/Broker SPO Partners II, L.P. 08/07/09 Sell 11,545 19.95 Open Market/Broker SPO Partners II, L.P. 08/07/09 Sell 9,868 19.96 Open Market/Broker SPO Partners II, L.P. 08/07/09 Sell 6,511 19.97 Open Market/Broker SPO Partners II, L.P. 08/07/09 Sell 3,765 19.98 Open Market/Broker SPO Partners II, L.P. 08/07/09 Sell 5,822 19.99 Open Market/Broker

Page 30 of 39 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. 08/07/09 Sell 7,400 20.00 Open Market/Broker SPO Partners II, L.P. 08/07/09 Sell 3,059 20.01 Open Market/Broker SPO Partners II, L.P. 08/07/09 Sell 3,453 20.02 Open Market/Broker SPO Partners II, L.P. 08/07/09 Sell 1,283 20.03 Open Market/Broker SPO Partners II, L.P. 08/07/09 Sell 888 20.04 Open Market/Broker SPO Partners II, L.P. 08/07/09 Sell 789 20.05 Open Market/Broker SPO Partners II, L.P. 08/07/09 Sell 888 20.06 Open Market/Broker SPO Partners II, L.P. 08/07/09 Sell 3,848 20.07 Open Market/Broker SPO Partners II, L.P. 08/07/09 Sell 3,196 20.08 Open Market/Broker SPO Partners II, L.P. 08/07/09 Sell 2,317 20.09 Open Market/Broker SPO Partners II, L.P. 08/07/09 Sell 2,133 20.10 Open Market/Broker SPO Partners II, L.P. 08/07/09 Sell 1,578 20.11 Open Market/Broker SPO Partners II, L.P. 08/07/09 Sell 2,664 20.12 Open Market/Broker SPO Partners II, L.P. 08/07/09 Sell 1,076 20.13 Open Market/Broker SPO Partners II, L.P. 08/07/09 Sell 4,728 20.14 Open Market/Broker SPO Partners II, L.P. 08/07/09 Sell 151,432 20.15 Open Market/Broker SPO Partners II, L.P. 08/07/09 Sell 1,343 20.16 Open Market/Broker SPO Partners II, L.P. 08/07/09 Sell 3,158 20.17 Open Market/Broker SPO Partners II, L.P. 08/07/09 Sell 1,283 20.18 Open Market/Broker SPO Partners II, L.P. 08/07/09 Sell 1,283 20.19 Open Market/Broker SPO Partners II, L.P. 08/07/09 Sell 2,103 20.20 Open Market/Broker SPO Partners II, L.P. 08/07/09 Sell 1,578 20.21 Open Market/Broker SPO Partners II, L.P. 08/07/09 Sell 1,578 20.22 Open Market/Broker SPO Partners II, L.P. 08/07/09 Sell 2,270 20.23 Open Market/Broker SPO Partners II, L.P. 08/07/09 Sell 592 20.24 Open Market/Broker SPO Partners II, L.P. 08/07/09 Sell 99 20.26 Open Market/Broker SPO Partners II, L.P. 08/07/09 Sell 395 20.28 Open Market/Broker SPO Partners II, L.P. 08/07/09 Sell 198 20.29 Open Market/Broker SPO Partners II, L.P. 08/07/09 Sell 99 20.30 Open Market/Broker SPO Partners II, L.P. 08/07/09 Sell 296 20.31 Open Market/Broker SPO Partners II, L.P. 08/07/09 Sell 1,086 20.32 Open Market/Broker SPO Partners II, L.P. 08/07/09 Sell 888 20.33 Open Market/Broker SPO Partners II, L.P. 08/07/09 Sell 987 20.34 Open Market/Broker SPO Partners II, L.P. 08/07/09 Sell 1,382 20.35 Open Market/Broker SPO Partners II, L.P. 08/07/09 Sell 1,578 20.36 Open Market/Broker SPO Partners II, L.P. 08/07/09 Sell 2,466 20.37 Open Market/Broker SPO Partners II, L.P. 08/07/09 Sell 592 20.38 Open Market/Broker The Elizabeth R. and William J. 08/07/09 Sell 5 19.90 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/07/09 Sell 6 19.91 Open Market/Broker Patterson Foundation

Page 31 of 39 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. 08/07/09 Sell 5 19.92 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/07/09 Sell 1 19.93 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/07/09 Sell 5 19.94 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/07/09 Sell 26 19.95 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/07/09 Sell 22 19.96 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/07/09 Sell 15 19.97 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/07/09 Sell 9 19.98 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/07/09 Sell 13 19.99 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/07/09 Sell 17 20.00 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/07/09 Sell 7 20.01 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/07/09 Sell 8 20.02 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/07/09 Sell 3 20.03 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/07/09 Sell 2 20.04 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/07/09 Sell 2 20.05 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/07/09 Sell 2 20.06 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/07/09 Sell 9 20.07 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/07/09 Sell 7 20.08 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/07/09 Sell 5 20.09 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/07/09 Sell 5 20.10 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/07/09 Sell 4 20.11 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/07/09 Sell 6 20.12 Open Market/Broker Patterson Foundation

Page 32 of 39 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. 08/07/09 Sell 2 20.13 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/07/09 Sell 11 20.14 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/07/09 Sell 345 20.15 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/07/09 Sell 3 20.16 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/07/09 Sell 7 20.17 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/07/09 Sell 3 20.18 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/07/09 Sell 3 20.19 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/07/09 Sell 5 20.20 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/07/09 Sell 4 20.21 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/07/09 Sell 4 20.22 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/07/09 Sell 5 20.23 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/07/09 Sell 1 20.24 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/07/09 Sell 1 20.28 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/07/09 Sell 1 20.31 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/07/09 Sell 2 20.32 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/07/09 Sell 2 20.33 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/07/09 Sell 2 20.34 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/07/09 Sell 3 20.35 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/07/09 Sell 4 20.36 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/07/09 Sell 6 20.37 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/07/09 Sell 2 20.38 Open Market/Broker Patterson Foundation

Page 33 of 39 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 08/07/09 Sell 26 19.90 Open Market/Broker William E. Oberndorf IRA 08/07/09 Sell 29 19.91 Open Market/Broker William E. Oberndorf IRA 08/07/09 Sell 24 19.92 Open Market/Broker William E. Oberndorf IRA 08/07/09 Sell 7 19.93 Open Market/Broker William E. Oberndorf IRA 08/07/09 Sell 27 19.94 Open Market/Broker William E. Oberndorf IRA 08/07/09 Sell 131 19.95 Open Market/Broker William E. Oberndorf IRA 08/07/09 Sell 112 19.96 Open Market/Broker William E. Oberndorf IRA 08/07/09 Sell 74 19.97 Open Market/Broker William E. Oberndorf IRA 08/07/09 Sell 43 19.98 Open Market/Broker William E. Oberndorf IRA 08/07/09 Sell 66 19.99 Open Market/Broker William E. Oberndorf IRA 08/07/09 Sell 84 20.00 Open Market/Broker William E. Oberndorf IRA 08/07/09 Sell 35 20.01 Open Market/Broker William E. Oberndorf IRA 08/07/09 Sell 39 20.02 Open Market/Broker William E. Oberndorf IRA 08/07/09 Sell 15 20.03 Open Market/Broker William E. Oberndorf IRA 08/07/09 Sell 10 20.04 Open Market/Broker William E. Oberndorf IRA 08/07/09 Sell 9 20.05 Open Market/Broker William E. Oberndorf IRA 08/07/09 Sell 10 20.06 Open Market/Broker William E. Oberndorf IRA 08/07/09 Sell 44 20.07 Open Market/Broker William E. Oberndorf IRA 08/07/09 Sell 36 20.08 Open Market/Broker William E. Oberndorf IRA 08/07/09 Sell 26 20.09 Open Market/Broker William E. Oberndorf IRA 08/07/09 Sell 24 20.10 Open Market/Broker William E. Oberndorf IRA 08/07/09 Sell 18 20.11 Open Market/Broker William E. Oberndorf IRA 08/07/09 Sell 30 20.12 Open Market/Broker William E. Oberndorf IRA 08/07/09 Sell 12 20.13 Open Market/Broker William E. Oberndorf IRA 08/07/09 Sell 54 20.14 Open Market/Broker William E. Oberndorf IRA 08/07/09 Sell 1,725 20.15 Open Market/Broker William E. Oberndorf IRA 08/07/09 Sell 15 20.16 Open Market/Broker William E. Oberndorf IRA 08/07/09 Sell 36 20.17 Open Market/Broker William E. Oberndorf IRA 08/07/09 Sell 15 20.18 Open Market/Broker William E. Oberndorf IRA 08/07/09 Sell 15 20.19 Open Market/Broker William E. Oberndorf IRA 08/07/09 Sell 24 20.20 Open Market/Broker William E. Oberndorf IRA 08/07/09 Sell 18 20.21 Open Market/Broker William E. Oberndorf IRA 08/07/09 Sell 18 20.22 Open Market/Broker William E. Oberndorf IRA 08/07/09 Sell 26 20.23 Open Market/Broker William E. Oberndorf IRA 08/07/09 Sell 7 20.24 Open Market/Broker William E. Oberndorf IRA 08/07/09 Sell 1 20.26 Open Market/Broker William E. Oberndorf IRA 08/07/09 Sell 4 20.28 Open Market/Broker William E. Oberndorf IRA 08/07/09 Sell 2 20.29 Open Market/Broker William E. Oberndorf IRA 08/07/09 Sell 1 20.30 Open Market/Broker William E. Oberndorf IRA 08/07/09 Sell 3 20.31 Open Market/Broker William E. Oberndorf IRA 08/07/09 Sell 12 20.32 Open Market/Broker William E. Oberndorf IRA 08/07/09 Sell 10 20.33 Open Market/Broker

Page 34 of 39 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 08/07/09 Sell 11 20.34 Open Market/Broker William E. Oberndorf IRA 08/07/09 Sell 16 20.35 Open Market/Broker William E. Oberndorf IRA 08/07/09 Sell 18 20.36 Open Market/Broker William E. Oberndorf IRA 08/07/09 Sell 28 20.37 Open Market/Broker William E. Oberndorf IRA 08/07/09 Sell 10 20.38 Open Market/Broker SPO Partners II, L.P. 08/10/09 Sell 4,662 19.60 Open Market/Broker SPO Partners II, L.P. 08/10/09 Sell 6,692 19.61 Open Market/Broker SPO Partners II, L.P. 08/10/09 Sell 2,449 19.62 Open Market/Broker SPO Partners II, L.P. 08/10/09 Sell 6,161 19.63 Open Market/Broker SPO Partners II, L.P. 08/10/09 Sell 3,375 19.64 Open Market/Broker SPO Partners II, L.P. 08/10/09 Sell 9,176 19.65 Open Market/Broker SPO Partners II, L.P. 08/10/09 Sell 10,354 19.66 Open Market/Broker SPO Partners II, L.P. 08/10/09 Sell 5,729 19.67 Open Market/Broker SPO Partners II, L.P. 08/10/09 Sell 9,786 19.68 Open Market/Broker SPO Partners II, L.P. 08/10/09 Sell 18,002 19.69 Open Market/Broker SPO Partners II, L.P. 08/10/09 Sell 10,087 19.70 Open Market/Broker SPO Partners II, L.P. 08/10/09 Sell 10,952 19.71 Open Market/Broker SPO Partners II, L.P. 08/10/09 Sell 4,386 19.72 Open Market/Broker SPO Partners II, L.P. 08/10/09 Sell 2,581 19.73 Open Market/Broker SPO Partners II, L.P. 08/10/09 Sell 7,320 19.74 Open Market/Broker SPO Partners II, L.P. 08/10/09 Sell 13,516 19.75 Open Market/Broker SPO Partners II, L.P. 08/10/09 Sell 3,124 19.76 Open Market/Broker SPO Partners II, L.P. 08/10/09 Sell 2,605 19.77 Open Market/Broker SPO Partners II, L.P. 08/10/09 Sell 1,578 19.78 Open Market/Broker SPO Partners II, L.P. 08/10/09 Sell 480 19.79 Open Market/Broker SPO Partners II, L.P. 08/10/09 Sell 101 19.80 Open Market/Broker SPO Partners II, L.P. 08/10/09 Sell 100 19.81 Open Market/Broker SPO Partners II, L.P. 08/10/09 Sell 287 19.82 Open Market/Broker SPO Partners II, L.P. 08/10/09 Sell 149 19.83 Open Market/Broker SPO Partners II, L.P. 08/10/09 Sell 48 19.86 Open Market/Broker The Elizabeth R. and William J. 08/10/09 Sell 10 19.60 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/10/09 Sell 15 19.61 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/10/09 Sell 5 19.62 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/10/09 Sell 14 19.63 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/10/09 Sell 8 19.64 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/10/09 Sell 21 19.65 Open Market/Broker Patterson Foundation

Page 35 of 39 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. 08/10/09 Sell 23 19.66 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/10/09 Sell 13 19.67 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/10/09 Sell 22 19.68 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/10/09 Sell 40 19.69 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/10/09 Sell 23 19.70 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/10/09 Sell 25 19.71 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/10/09 Sell 10 19.72 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/10/09 Sell 6 19.73 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/10/09 Sell 16 19.74 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/10/09 Sell 30 19.75 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/10/09 Sell 7 19.76 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/10/09 Sell 6 19.77 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/10/09 Sell 4 19.78 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/10/09 Sell 1 19.79 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/10/09 Sell 1 19.82 Open Market/Broker Patterson Foundation William E. Oberndorf IRA 08/10/09 Sell 52 19.60 Open Market/Broker William E. Oberndorf IRA 08/10/09 Sell 75 19.61 Open Market/Broker William E. Oberndorf IRA 08/10/09 Sell 27 19.62 Open Market/Broker William E. Oberndorf IRA 08/10/09 Sell 69 19.63 Open Market/Broker William E. Oberndorf IRA 08/10/09 Sell 38 19.64 Open Market/Broker William E. Oberndorf IRA 08/10/09 Sell 103 19.65 Open Market/Broker William E. Oberndorf IRA 08/10/09 Sell 116 19.66 Open Market/Broker William E. Oberndorf IRA 08/10/09 Sell 64 19.67 Open Market/Broker William E. Oberndorf IRA 08/10/09 Sell 110 19.68 Open Market/Broker William E. Oberndorf IRA 08/10/09 Sell 202 19.69 Open Market/Broker William E. Oberndorf IRA 08/10/09 Sell 113 19.70 Open Market/Broker William E. Oberndorf IRA 08/10/09 Sell 123 19.71 Open Market/Broker

Page 36 of 39 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 08/10/09 Sell 49 19.72 Open Market/Broker William E. Oberndorf IRA 08/10/09 Sell 29 19.73 Open Market/Broker William E. Oberndorf IRA 08/10/09 Sell 82 19.74 Open Market/Broker William E. Oberndorf IRA 08/10/09 Sell 152 19.75 Open Market/Broker William E. Oberndorf IRA 08/10/09 Sell 35 19.76 Open Market/Broker William E. Oberndorf IRA 08/10/09 Sell 29 19.77 Open Market/Broker William E. Oberndorf IRA 08/10/09 Sell 18 19.78 Open Market/Broker William E. Oberndorf IRA 08/10/09 Sell 5 19.79 Open Market/Broker William E. Oberndorf IRA 08/10/09 Sell 1 19.80 Open Market/Broker William E. Oberndorf IRA 08/10/09 Sell 1 19.81 Open Market/Broker William E. Oberndorf IRA 08/10/09 Sell 3 19.82 Open Market/Broker William E. Oberndorf IRA 08/10/09 Sell 2 19.83 Open Market/Broker William E. Oberndorf IRA 08/10/09 Sell 2 19.86 Open Market/Broker SPO Partners II, L.P. 08/11/09 Sell 14,367 19.60 Open Market/Broker SPO Partners II, L.P. 08/11/09 Sell 6,332 19.61 Open Market/Broker SPO Partners II, L.P. 08/11/09 Sell 3,749 19.62 Open Market/Broker SPO Partners II, L.P. 08/11/09 Sell 6,922 19.63 Open Market/Broker SPO Partners II, L.P. 08/11/09 Sell 3,816 19.64 Open Market/Broker SPO Partners II, L.P. 08/11/09 Sell 9,330 19.65 Open Market/Broker SPO Partners II, L.P. 08/11/09 Sell 6,283 19.66 Open Market/Broker SPO Partners II, L.P. 08/11/09 Sell 6,657 19.67 Open Market/Broker SPO Partners II, L.P. 08/11/09 Sell 7,794 19.68 Open Market/Broker SPO Partners II, L.P. 08/11/09 Sell 14,507 19.69 Open Market/Broker SPO Partners II, L.P. 08/11/09 Sell 28,088 19.70 Open Market/Broker SPO Partners II, L.P. 08/11/09 Sell 13,752 19.71 Open Market/Broker SPO Partners II, L.P. 08/11/09 Sell 5,983 19.72 Open Market/Broker SPO Partners II, L.P. 08/11/09 Sell 7,159 19.73 Open Market/Broker SPO Partners II, L.P. 08/11/09 Sell 22,495 19.74 Open Market/Broker SPO Partners II, L.P. 08/11/09 Sell 42,740 19.75 Open Market/Broker SPO Partners II, L.P. 08/11/09 Sell 18,165 19.76 Open Market/Broker SPO Partners II, L.P. 08/11/09 Sell 16,570 19.77 Open Market/Broker SPO Partners II, L.P. 08/11/09 Sell 5,130 19.78 Open Market/Broker SPO Partners II, L.P. 08/11/09 Sell 3,551 19.79 Open Market/Broker SPO Partners II, L.P. 08/11/09 Sell 4,718 19.80 Open Market/Broker SPO Partners II, L.P. 08/11/09 Sell 492 19.81 Open Market/Broker The Elizabeth R. and William J. 08/11/09 Sell 35 19.60 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/11/09 Sell 15 19.61 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/11/09 Sell 9 19.62 Open Market/Broker Patterson Foundation

Page 37 of 39 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. 08/11/09 Sell 17 19.63 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/11/09 Sell 9 19.64 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/11/09 Sell 23 19.65 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/11/09 Sell 15 19.66 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/11/09 Sell 16 19.67 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/11/09 Sell 19 19.68 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/11/09 Sell 35 19.69 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/11/09 Sell 68 19.70 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/11/09 Sell 33 19.71 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/11/09 Sell 14 19.72 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/11/09 Sell 17 19.73 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/11/09 Sell 54 19.74 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/11/09 Sell 103 19.75 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/11/09 Sell 44 19.76 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/11/09 Sell 40 19.77 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/11/09 Sell 12 19.78 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/11/09 Sell 9 19.79 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/11/09 Sell 11 19.80 Open Market/Broker Patterson Foundation The Elizabeth R. and William J. 08/11/09 Sell 2 19.81 Open Market/Broker Patterson Foundation William E. Oberndorf IRA 08/11/09 Sell 162 19.60 Open Market/Broker William E. Oberndorf IRA 08/11/09 Sell 71 19.61 Open Market/Broker William E. Oberndorf IRA 08/11/09 Sell 42 19.62 Open Market/Broker William E. Oberndorf IRA 08/11/09 Sell 78 19.63 Open Market/Broker

Page 38 of 39 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 08/11/09 Sell 43 19.64 Open Market/Broker William E. Oberndorf IRA 08/11/09 Sell 105 19.65 Open Market/Broker William E. Oberndorf IRA 08/11/09 Sell 71 19.66 Open Market/Broker William E. Oberndorf IRA 08/11/09 Sell 75 19.67 Open Market/Broker William E. Oberndorf IRA 08/11/09 Sell 88 19.68 Open Market/Broker William E. Oberndorf IRA 08/11/09 Sell 163 19.69 Open Market/Broker William E. Oberndorf IRA 08/11/09 Sell 316 19.70 Open Market/Broker William E. Oberndorf IRA 08/11/09 Sell 155 19.71 Open Market/Broker William E. Oberndorf IRA 08/11/09 Sell 67 19.72 Open Market/Broker William E. Oberndorf IRA 08/11/09 Sell 81 19.73 Open Market/Broker William E. Oberndorf IRA 08/11/09 Sell 253 19.74 Open Market/Broker William E. Oberndorf IRA 08/11/09 Sell 481 19.75 Open Market/Broker William E. Oberndorf IRA 08/11/09 Sell 205 19.76 Open Market/Broker William E. Oberndorf IRA 08/11/09 Sell 187 19.77 Open Market/Broker William E. Oberndorf IRA 08/11/09 Sell 58 19.78 Open Market/Broker William E. Oberndorf IRA 08/11/09 Sell 40 19.79 Open Market/Broker William E. Oberndorf IRA 08/11/09 Sell 53 19.80 Open Market/Broker William E. Oberndorf IRA 08/11/09 Sell 6 19.81 Open Market/Broker

Page 39 of 39 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 12, 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.