Exhibit 12

Ratio of Earnings To Fixed Charges

          The following table shows our ratio of earnings to fixed charges for each of the periods indicated (dollars in thousands):

	Three Months Ended
	March 31,		Year Ended December 31,
	2007		2006		2005		2004		2003		2002
Interest expense	$	7,700	$	28,419	$	13,011	$	11,186	$	12,848	$	21,539
Estimate of interest expense included in rental expense		624		2,296		2,064		1,696		1,456		1,184
FIN 48 interest expense booked to income tax expense		—		295		59		460		—		—
Total fixed charges		8,324		31,010		15,134		13,342		14,304		22,723
Income before income taxes	$	48,097	$	172,574	$	111,980	$	128,564	$	108,729	$	75,577
Total fixed charges		8,324		31,010		15,134		13,342		14,304		22,723
Earnings		56,421		203,584		127,114		141,906		123,033		98,300
Ratio of earnings to fixed charges(1)		6.78		6.57		8.40		10.64		8.60		4.33

(1) For the purpose of calculating the ratio of earnings to fixed charges, earnings consist of income before income taxes plus fixed charges. Fixed charges consist of (i) interest on all indebtedness (including capital leases) and amortization of debt discount and deferred financing fees, (ii) the interest factor attributable to rentals and (iii) interest on liabilities associated with Financial Accounting Standards Board Interpretation No. 48 (“FIN 48”), Accounting for Uncertainty in Income Taxes.