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                                                                    EXHIBIT 12.1


                     STATEMENT REGARDING THE COMPUTATION OF
           RATIO OF FIXED CHARGES AND PREFERENCE DIVIDENDS TO EARNINGS

<Table>
<Caption>
                                                  Nine months to                     Fiscal year ended December 31
                                                  September 30, 2004     2003          2002        2001       2000        1999
                                                 -----------------------------------------------------------------------------------
                                                                                                      
Earnings per Financial Statements                857,214               1,417,482     76,549      (146,414)   542,982    364,963
Add (deduct):

     Provision for income taxes                  304,082               278,347       (115,688)   (90,951)    93,908     28,684

     Fixed charges                               158,418               205,758       215,161     219,849     242,783    126,138
                                                 -----------------------------------------------------------------------------------
Earnings for Computation
                                                 1,319,714             1,901,587     176,022     (17,516)    879,673    519,785
                                                 ===================================================================================

FIXED CHARGES

Interest Expense                                 139,668               177,425       193,494     199,182     221,450    105,138

One third of payments under operating leases     18,750                28,333        21,667      20,667      21,333     21,000
                                                 -----------------------------------------------------------------------------------
  Total Fixed Charges
                                                 158,418               205,758       215,161     219,849     242,783    126,138
                                                 ===================================================================================

Ratio of Earnings to Fixed Charges               8.3x                  9.2x              (1)         (2)     3.6x       4.1x
                                                 ===================================================================================
Preferred Share Dividends                                                                                               -
                                                 33,761                36,009        25,662      25,594      18,391
                                                 -----------------------------------------------------------------------------------
   Total Fixed Charges and
       Preferred Share Dividends                 192,179               241,767       240,823     245,443     261,174    126,138
                                                 ===================================================================================
                                                                                         (1)         (2)
Ratio of Earnings to Fixed Charges and
Preferred Share Dividends                        6.9x                  7.9x                                  3.4x       4.1x
                                                 ===================================================================================
</Table>

(1)  Earnings for the year ended December 31, 2002 were insufficient to cover
     fixed charges by $39 million and combined fixed charges and preferred share
     dividends by $65 million.

(2)  Earnings for the year ended December 31, 2001 were insufficient to cover
     fixed charges by $237 million and combined fixed charges and preferred
     share dividends by $263 million.