EXHIBIT 12 Computation of Ratio of Earnings to Combined Fixed Charges and Preferred Stock Dividends (Dollars in thousands) Three Months ended September 30, Nine Months Ended September 30, -------------------------------- --------------------------------- 1997 1996 1997 1996 ----------- ----------- ---------- --------- Net income before extraordinary item $23,309 $9,818 $55,099 $27,544 Add: Portion of rents representative of the interest factor 111 62 301 177 Interest on indebtedness 19,346 13,530 58,265 35,413 ----------- -------------- ------------- ----------- Earnings $42,766 $23,410 $113,665 $63,134 =========== ============== ============= =========== Fixed charges and preferred stock dividend: Interest on indebtedness $19,346 $13,530 $58,265 $35,413 Capitalized interest 852 143 2,082 397 Portion of rents representative of the interest factor 111 62 301 177 ------------ ---------------- -------------- ----------- Fixed charges 20,309 13,735 60,648 35,987 ------------ ---------------- -------------- ----------- Add: Preferred stock dividend 5,653 2,428 11,692 7,284 ------------ ---------------- -------------- ----------- Combined fixed charges and preferred stock dividend $25,962 $16,163 $72,340 $43,271 ============ ================ ============== =========== Ratio of earnings to fixed charges 2.11 x 1.70 x 1.87 x 1.75 x Ratio of earnings to combined fixed charges and preferred stock dividend 1.65 1.45 1.57 1.46