EXHIBIT 12 Computation of Ratio of Earnings to Combined Fixed Charges and Preferred Stock Dividends (Dollars in thousands) Three Months ended March 31, -------------------------------------------------- 2000 1999 ----------------------- ---------------------- Net income before extraordinary items $18,808 $20,082 Add: Portion of rents representative of the interest factor 244 259 Interest on indebtedness 39,075 38,079 ----------------------- ---------------------- Earnings $58,127 $58,420 ======================= ====================== Fixed charges and preferred stock dividend: Interest on indebtedness $39,075 $38,079 Capitalized interest 964 1,667 Portion of rents representative of the interest factor 244 259 ----------------------- ---------------------- Fixed charges 40,283 40,005 ----------------------- ---------------------- Add: Preferred stock dividend 9,408 9,439 ----------------------- ---------------------- Combined fixed charges and preferred stock dividend $49,691 $49,444 ======================= ====================== Ratio of earnings to fixed charges 1.44 x 1.46 x Ratio of earnings to combined fixed charges and preferred stock dividend 1.17 1.18