Exhibit 12.1

Computation of Ratio of Earnings to Fixed Charges
(Dollars in thousands, except Ratio Data)

	Years Ended July 31,
	2008		2007		2006		2005		2004
Earnings:
Income before income taxes	$	186,187	$	151,927	$	144,688	$	115,418	$	70,327
Add back:
Fixed charges less interest capitalized		29,059		25,158		15,572		9,809		2,362
Less:
Preferred stock dividends and premium on redemption of preferred stock		—		—		—		—		—
Total earnings	$	215,246	$	177,085	$	160,260	$	125,227	$	72,689
Fixed Charges:
Interest, capitalized and expensed	$	26,385	$	22,936	$	14,131	$	8,470	$	1,231
Amortization of debt expense		341		284		252		214		61
Interest portion of rent expense		2,333		1,936		1,290		1,192		1,070
Preferred stock dividends and premium on redemption of preferred stock		—		—		—		—		—
Total Fixed Charges	$	29,059	$	25,156	$	15,673	$	9,876	$	2,362
Ratio of Earnings to Fixed Charges ( 1)		7.4		7.0		10.2		12.7		30.8

(1) The ratio of earnings to fixed charges has been computed by adding income before income taxes and fixed charges less interest capitalized and subtracting preferred stock dividends and premium on redemption of preferred stock to derive total earnings, and dividing total earnings by fixed charges. Fixed charges consist of interest expensed and capitalized, amortization of debt expense, 8.5% of rent expense which is deemed representative of an interest factor and preferred stock dividends and premium on redemption of preferred stock.