<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>                                          21,856                   5,717                  13,761                  20,008
                  29,639
<SECURITIES>                                         0                       0                       0                       0
                       0
<RECEIVABLES>                                  382,010                 377,549                 365,639                 338,602
                 577,021
<ALLOWANCES>                                         0                       0                       0                       0
                       0
<INVENTORY>                                     29,669                  30,632                  35,988                  37,938
                  30,500
<CURRENT-ASSETS>                               474,921                 486,635                 496,939                 468,565
                 693,290
<PP&E>                                       5,200,306               4,934,701               5,048,611               5,090,707
               5,084,283
<DEPRECIATION>                               2,671,139               2,593,642               2,650,301               2,641,253
               2,650,419
<TOTAL-ASSETS>                               3,648,520               3,574,253               3,456,440               3,488,317
               3,774,659
<CURRENT-LIABILITIES>                          701,338                 674,880                 718,489                 627,594
                 848,837
<BONDS>                                        861,382                 764,443                 763,324                 867,606
                 872,255
<PREFERRED-MANDATORY>                                0                       0                       0                       0
                       0
<PREFERRED>                                          0                       0                       0                       0
                       0
<COMMON>                                        87,230                  87,244                  87,244                  87,244
                  87,233
<OTHER-SE>                                   1,519,619               1,412,189               1,429,382               1,449,918
               1,497,131
<TOTAL-LIABILITY-AND-EQUITY>                 3,648,520               3,574,253               3,456,440               3,488,317
               3,774,659
<SALES>                                        955,960                 583,189               1,100,778               1,732,511
               2,556,822
<TOTAL-REVENUES>                             1,072,143                 695,604               1,332,934               2,076,730
               3,039,014
<CGS>                                          807,984                 460,951                 856,877               1,358,430
               2,038,846
<TOTAL-COSTS>                                  849,919                 500,209                 939,154               1,486,719
               2,211,608
<OTHER-EXPENSES>                                68,483                  67,373                 138,751                 213,421
                 288,192
<LOSS-PROVISION>                                     0                       0                       0                       0
                       0
<INTEREST-EXPENSE>                              20,646                  22,860                  45,457                  66,105
                  86,946
<INCOME-PRETAX>                                100,205                  66,183                 127,571                 196,513
                 294,304
<INCOME-TAX>                                    33,359                  20,614                  41,407                  62,315
                  93,115
<INCOME-CONTINUING>                             66,846                  45,569                  86,164                 134,198
                 201,189
<DISCONTINUED>                                       0                       0                       0                       0
                       0
<EXTRAORDINARY>                                      0                       0                       0                       0
                       0
<CHANGES>                                            0                       0                       0                       0
                       0
<NET-INCOME>                                    66,846                  45,569                  86,164                 134,198
                 201,189
<EPS-PRIMARY>                                      .78                     .53                    1.00                    1.56
                    2.33
<EPS-DILUTED>                                      .78                     .53                    1.00                    1.56
                    2.33
        

</TABLE>