Exhibit 12.1



Ratio of Earnings to Fixed Charges



|                                                    |  |                                  |        |                          |   |         |   |      |   |         |  |      |         |  |   |        |  |   |         |  
|--------------------------------------------------- |  | -------------------------------- | ------ | ------------------------ | - | ------- | - | ---- | - | ------- |  | ---- | ------- |  | - | ------ |  | - | ------- | -
|                                                    |  | THREE MONTHSENDED MARCH 31, 2006 |        | YEARS ENDED DECEMBER 31, |  
|                                                    |  |                                  |        |                          |  
|                                                    |  |                                  | 2005   |                          |   | 2004    |   | 2003 |   | 2002    |  | 2001 |        
|                                                    |  |                                  |        |                          |   |         |   |      |   |         |  |      |         |  |   |        |  |   |         |  
|(in thousands, except ratios)                       |  |                                  |        |                          |   |         |   |      |   |         |  |      |         | 
|                                                    |  |                                  |        |                          |   |        
|Income (loss) before income taxes                   |  | $                                | 62,834 |                          | $ | 230,654 | 3 |      | $ | 174,039 |  | $    | 87,716  |  | $ | 36,087 |  | $ | (98,662 | )
|Add fixed charges                                   |  |                                  |        |                          |   |         |   |      |   |         |  |      |         |  |   |        |  |   |         |  
|Interest expense                                    |  |                                  | 357    |                          |   | 7,618   | 3 |      |   | 3,828   |  |      | 9,765   |  |   | 15,364 |  |   | 17,231  |  
|Interest portion of rent expense                    |  |                                  | 1,504  |                          |   | 6,280   |   |      |   | 6,185   |  |      | 6,113   |  |   | 6,235  |  |   | 7,005   |  
|                                                    |  |                                  |        |                          |   |         |   |      |   |         |  |      |         |  |   |        |  |   |         |  
|Income (loss) before income taxes and fixed charges |  | $                                | 64,695 |                          | $ | 244,552 |   |      | $ | 184,052 |  | $    | 103,594 |  | $ | 57,686 |  | $ | (74,426 | )
|                                                    |  |                                  |        |                          |   |         |   |      |   |         |  |      |         |  |   |        |  |   |         |  
|Fixed charges                                       |  |                                  |        |                          |   |         |   |      |   |         |  |      |         |  |   |        |  |   |         |  
|Interest expense                                    |  | $                                | 357    |                          | $ | 7,6183  |   |      | $ | 3,828   |  | $    | 9,765   |  | $ | 15,364 |  | $ | 17,231  |  
|Interest portion of rent expense                    |  |                                  | 1,504  |                          |   | 6,280   |   |      |   | 6,185   |  |      | 6,113   |  |   | 6,235  |  |   | 7,005   |  
|                                                    |  |                                  |        |                          |   |         |   |      |   |         |  |      |         |  |   |        |  |   |         |  
|Fixed charges                                       |  | $                                | 1,861  |                          | $ | 13,8983 |   |      | $ | 10,013  |  | $    | 15,878  |  | $ | 21,599 |  | $ | 24,236  |  
|                                                    |  |                                  |        |                          |   |         |   |      |   |         |  |      |         |  |   |        |  |   |         |  
|Ratio of earnings to fixed charges1                 |  |                                  | 34.8   |                          |   | 17.63   |   |      |   | 18.4    |  |      | 6.5     |  |   | 2.7    |  |   |        |  
|Deficiency of earnings to fixed charges2            |  |                                  |       |                          |   |        |   |      |   |        |  |      |        |  |   |       |  | $ | (98,662 | )
|                                                    | 



|1 |  | Ratio of earnings to fixed charges means the ratio of income before fixed charges and income taxes to fixed charges, where fixed charges are the aggregate of interest expense, including
amortization of debt issuance costs, and an allocation of rental charges to approximate equivalent interest.
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|2 |  | Due to a net loss incurred in 2001, the ratio of earnings to fixed charges in that year was less than 1:1. We would have had to generate additional earnings in the amounts indicated in the
table to have achieved a ratio of 1:1.
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|3 |  | Included as a deduction from income before income taxes and as an addition to interest expense in 2005 is accelerated amortization of debt issuance costs in the amount of $5.0 million.
Excluding this amortization, the ratio of earnings to fixed charges would have been 27.6 for the year ended December 31, 2005.
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