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|                                                          |   | Three      Months   |    |   |                         |   |    |   |   |   |    |   |   |   |    |   |   |   |
|---------------------------------------------------------------|--------|---------------------|---------|--------|------------------------------|--------|---------|--------|--------|--------|---------|--------|--------|--------|---------|--------|--------|--------|
|                                                          |   | Ended               |    |   | Year      Ended December 31, |   |
|                                                          |   | March      31, 2008 |    |   | 2007                         |   |    | 2006   |   |   | 2005    |   |   | 2004   |    |   | 2003   |   |
| Fixed      charges, as defined by the Securities and Exchange |   |                |    |   |                         |   |    |   |   |   |    |   |   |   |    |   |   |   |
| Commission:                                                   |   |                |    |   |                         |   |    |   |   |   |    |   |   |   |    |   |   |   |
|                                                          |   |                |    |   |                         |   |    |   |   |   |    |   |   |   |    |   |   |   |
| Interest      on long-term debt                               |   | $                   | 10,530  |   |                         | $      | 38,534  |   |   | $      | 40,541  |   |   | $      | 39,408  |   |   | $      | 36,801 |   |   | $ | 48,067 |   |
| Amortization      of debt premium, discount and expenses      |   |                | 1,149   |   |                         |   | 4,618   |   |   |   | 2,871   |   |   |   | 2,856   |   |   |   | 3,036 |   |   |   | 2,958 |   |
| Other      interest                                           |   |                | 2,492   |   |                         |   | 9,799   |   |   |   | 3,956   |   |   |   | 1,921   |   |   |   | 1,719 |   |   |   | 3,859 |   |
| Estimated      interest factor of lease rental charges        |   |                | 3,964   |   |                         |   | 16,630  |   |   |   | 16,448  |   |   |   | 16,954  |   |   |   | 16,406 |   |   |   | 17,007 |   |
| Interest      capitalized                                     |   |                | 114     |   |                         |   | 3,738   |   |   |   | 1,946   |   |   |   | 1,054   |   |   |   | 752 |   |   |   | 909 |   |
|                                                          |   |                |    |   |                         |   |    |   |   |   |    |   |   |   |    |   |   |   |   |   |   |   |   |   |
|                                                          |   |                |    |   |                         |   |    |   |   |   |    |   |   |   |    |   |   |   |   |   |   |   |   |   |
|      Total      Fixed Charges        |   | $                   | 18,249  |   |                         | $      | 73,319  |   |   | $      | 65,762  |   |   | $      | 62,193  |   |   | $      | 58,714 |   |   | $ | 72,800 |   |
|                                                          |   |                |    |   |                         |   |    |   |   |   |    |   |   |   |    |   |   |   |   |   |   |   |   |   |
| Earnings,      as defined by the Securities and Exchange      |   |                |    |   |                         |   |    |   |   |   |    |   |   |   |    |   |   |   |   |   |   |   |   |   |
| Commission:                                                   |   |                |    |   |                         |   |    |   |   |   |    |   |   |   |    |   |   |   |   |   |   |   |   |   |
|                                                          |   |                |    |   |                         |   |    |   |   |   |    |   |   |   |    |   |   |   |   |   |   |   |   |   |
| Earnings      (loss) before income taxes                      |   | $                   | (44,066 | )      |                         | $      | 34,611  |   |   | $      | 89,657  |   |   | $      | 51,034  |   |   | $      | 114,690 |   |   | $ | 74,400 |   |
| Fixed      charges as above                                   |   |                | 18,249  |   |                         |   | 73,319  |   |   |   | 65,762  |   |   |   | 62,193  |   |   |   | 58,714 |   |   |   | 72,800 |   |
| Interest      capitalized                                     |   |                | (114    | )      |                         |   | (3,738  | )      |   |   | (1,946  | )      |   |   | (1,054  | )      |   |   | (752 | ) |   |   | (909 | ) |
|                                                          |   |                |    |   |                         |   |    |   |   |   |    |   |   |   |    |   |   |   |   |   |   |   |   |   |
| Earnings      (Loss) Available for Fixed Charges              |   | $                   | (25,931 | )      |                         | $      | 104,192 |   |   | $      | 153,473 |   |   | $      | 112,173 |   |   | $      | 172,652 |   |   | $ | 146,291 |   |
|                                                          |   |                |    |   |                         |   |    |   |   |   |    |   |   |   |    |   |   |   |   |   |   |   |   |   |
| Ratio      of Earnings to Fixed Charges                       |   |                | N/M     | *      |                         |   | 1.42    |   |   |   | 2.33    |   |   |   | 1.80    |   |   |   | 2.94 |   |   |   | 2.01 |   |
|                                                          |   |                |    |   |                         |   |    |   |   |   |    |   |   |   |    |   |   |   |   |   |   |   |   |   |

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