<ARTICLE> 5
<MULTIPLIER> 1,000
       
                             
<PERIOD-TYPE>                   12-MOS
<FISCAL-YEAR-END>                          DEC-31-1996
<PERIOD-END>                               DEC-31-1996
<CASH>                                          13,161
<SECURITIES>                                         0
<RECEIVABLES>                                  234,646
<ALLOWANCES>                                         0
<INVENTORY>                                     13,963
<CURRENT-ASSETS>                               268,156
<PP&E>                                       5,381,313
<DEPRECIATION>                               2,281,252
<TOTAL-ASSETS>                               3,432,430
<CURRENT-LIABILITIES>                          309,657
<BONDS>                                      1,235,706
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                          0
<COMMON>                                       114,030
<OTHER-SE>                                   1,404,486
<TOTAL-LIABILITY-AND-EQUITY>                 3,432,430
<SALES>                                        976,032
<TOTAL-REVENUES>                               977,151
<CGS>                                          679,439
<TOTAL-COSTS>                                  679,439
<OTHER-EXPENSES>                                35,911
<LOSS-PROVISION>                                     0
<INTEREST-EXPENSE>                              61,606
<INCOME-PRETAX>                                200,195
<INCOME-TAX>                                    78,768
<INCOME-CONTINUING>                            121,427
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                                   121,427
<EPS-PRIMARY>                                     1.42
<EPS-DILUTED>                                     1.42