<TABLE> <S> <C>

<ARTICLE> 5
<RESTATED> 
<MULTIPLIER> 1,000
       
<S>                             <C>                     <C>                     <C>                     <C>
<C>
<PERIOD-TYPE>                   3-MOS                   3-MOS                   6-MOS                   9-MOS
YEAR
<FISCAL-YEAR-END>                          DEC-31-1997             DEC-31-1996             DEC-31-1996             DEC-31-1996
             DEC-31-1996
<PERIOD-END>                               MAR-31-1997             MAR-31-1996             JUN-30-1996             SEP-30-1996
             DEC-31-1996
<CASH>                                             727                     763                   1,528                   1,800
                   2,316
<SECURITIES>                                         0                       0                       0                       0
                       0
<RECEIVABLES>                                   79,023                 109,459                  98,593                  93,949
                 103,736
<ALLOWANCES>                                         0                       0                       0                       0
                       0
<INVENTORY>                                     23,846                  29,211                  25,734                  27,416
                  24,197
<CURRENT-ASSETS>                               141,197                 285,732                 299,497                 219,718
                 156,522
<PP&E>                                       2,363,446               2,341,863               2,359,836               2,398,402
               2,422,845
<DEPRECIATION>                               1,488,098               1,516,726               1,526,910               1,532,312
               1,539,984
<TOTAL-ASSETS>                               1,205,337               1,450,204               1,283,693               1,239,072
               1,231,145
<CURRENT-LIABILITIES>                          101,546                 137,067                 153,024                 102,734
                 121,278
<BONDS>                                        305,216                 312,307                 311,739                 310,856
                 310,536
<PREFERRED-MANDATORY>                                0                       0                       0                       0
                       0
<PREFERRED>                                          0                       0                       0                       0
                       0
<COMMON>                                             4                       4                       4                       4
                       4
<OTHER-SE>                                     572,231                 587,515                 593,379                 603,915
                 567,177
<TOTAL-LIABILITY-AND-EQUITY>                 1,205,337               1,450,204               1,283,693               1,239,072
               1,231,145
<SALES>                                              0                       0                       0                       0
                       0
<TOTAL-REVENUES>                                99,166                 105,101                 201,082                 296,809
                 398,828
<CGS>                                                0                       0                       0                       0
                       0
<TOTAL-COSTS>                                   17,631                  19,860                  42,270                  66,916
                  83,955
<OTHER-EXPENSES>                                11,653                  12,401                  24,794                  36,110
                  48,292
<LOSS-PROVISION>                                     0                       0                       0                       0
                       0
<INTEREST-EXPENSE>                               6,803                  11,051                  21,999                  30,097
                  37,076
<INCOME-PRETAX>                                 46,638                  41,897                  71,712                 108,319
                 150,219
<INCOME-TAX>                                    17,972                  16,076                  27,627                  41,356
                  57,594
<INCOME-CONTINUING>                             28,666                  25,821                  44,085                  66,963
                  92,625
<DISCONTINUED>                                       0                       0                       0                       0
                       0
<EXTRAORDINARY>                                      0                       0                       0                       0
                       0
<CHANGES>                                            0                       0                       0                       0
                       0
<NET-INCOME>                                    28,666                  25,821                  44,085                  66,963
                  92,625
<EPS-PRIMARY>                                        0                       0                       0                       0
                       0
<EPS-DILUTED>                                        0                       0                       0                       0
                       0
        

</TABLE>