EXHIBIT 12 Computation of Ratios of Earnings to Fixed Charges 2001 2002 2003 2004 2005 ------------------------------------------------------------- Earnings: Income before income taxes $337,889 $347,318 $411,153 $647,432 $806,110 Interest expense 59,038 65,344 74,086 94,324 126,221 Rent expense 1,839 1,799 1,972 2,417 3,923 Amortization 897 1,037 2,689 1,085 1,079 ------------------------------------------------------------- $399,663 $415,498 $489,900 $745,258 $937,333 ============================================================= Fixed charges: Interest incurred $79,245 $90,331 $104,763 $113,452 $115,439 Rent expense 1,839 1,799 1,972 2,417 3,923 Amortization 897 1,037 2,689 1,085 1,079 ------------------------------------------------------------- $81,981 $93,167 $109,424 $116,954 $120,441 ============================================================= Ratio 4.88 4.46 4.48 6.37 7.78