<ARTICLE> 5 <MULTIPLIER> 1,000 <PERIOD-TYPE> 12-MOS <FISCAL-YEAR-END> DEC-31-1997 <PERIOD-END> DEC-31-1997 <CASH> 9,686 <SECURITIES> 0 <RECEIVABLES> 224,025 <ALLOWANCES> 0 <INVENTORY> 36,041 <CURRENT-ASSETS> 348,329 <PP&E> 6,380,663 <DEPRECIATION> 2,647,478 <TOTAL-ASSETS> 4,138,633 <CURRENT-LIABILITIES> 343,783 <BONDS> 1,501,380 <PREFERRED-MANDATORY> 0 <PREFERRED> 0 <COMMON> 118,098 <OTHER-SE> 1,611,079 <TOTAL-LIABILITY-AND-EQUITY> 4,138,633 <SALES> 983,773 <TOTAL-REVENUES> 1,176,273 <CGS> 807,065 <TOTAL-COSTS> 807,065 <OTHER-EXPENSES> 38,243 <LOSS-PROVISION> 0 <INTEREST-EXPENSE> 72,325 <INCOME-PRETAX> 258,640 <INCOME-TAX> 103,744 <INCOME-CONTINUING> 154,896 <DISCONTINUED> 0 <EXTRAORDINARY> 0 <CHANGES> 0 <NET-INCOME> 154,896 <EPS-PRIMARY> 1.71 <EPS-DILUTED> 1.65