EXHIBIT 12 Pro Forma Computation of Ratio of Earnings to Combined Fixed Charges and Preferred Stock Dividend Requirements Giving Effect to the Acquisition Discussed Herein Nine Months Ended Year Ended September 30, 2000 December 31, 1999 - ------------------------------------------------------------------------------------------------------------- (Thousands of Dollars) Fixed Charges, as defined Interest on long-term debt $ 67,670 $ 56,722 Other interest 15,634 18,993 Amortization of debt discount and expense 2,345 1,960 Interest on lease agreements 3,777 6,186 - ------------------------------------------------------------------------------------------------------------- Total Fixed Charges 89,426 83,861 Preferred dividend requirements 44,879 59,971 - ------------------------------------------------------------------------------------------------------------- Total fixed charges and preferred dividend requirements $134,305 $143,832 ============================================================================================================= Earnings before income taxes and income from equity investees 169,885 169,647 Total fixed charges 89,426 83,861 - ------------------------------------------------------------------------------------------------------------- Earnings available for combined fixed charges and preferred dividend requirements $259,311 $253,508 ============================================================================================================= Ratio of earnings to combined fixed charges and preferred dividend requirements 1.93x 1.76x ============================================================================================================= For purposes of computing the ratio of earnings to combined fixed charges and preferred dividend requirements, "earnings" consist of income before cumulative effect of a change in accounting principle plus fixed charges and income taxes, less undistributed income from equity investees. "Fixed charges" consists of interest charges, the amortization of debt discounts and issue costs and the representative interest portion of operating leases. "Preferred dividend requirements" consists of the pre-tax preferred dividend requirement.