<ARTICLE> 5 <MULTIPLIER> 1,000 <PERIOD-TYPE> 3-MOS <FISCAL-YEAR-END> DEC-31-1998 <PERIOD-START> JAN-01-1998 <PERIOD-END> MAR-31-1998 <CASH> 153,459 <SECURITIES> 13,696 <RECEIVABLES> 135,640 <ALLOWANCES> 0 <INVENTORY> 48,345 <CURRENT-ASSETS> 474,678 <PP&E> 883,126 <DEPRECIATION> 479,511 <TOTAL-ASSETS> 1,114,174 <CURRENT-LIABILITIES> 356,743 <BONDS> 111,008 <PREFERRED-MANDATORY> 0 <PREFERRED> 0 <COMMON> 80,614 <OTHER-SE> 519,902 <TOTAL-LIABILITY-AND-EQUITY> 1,114,174 <SALES> 488,970 <TOTAL-REVENUES> 488,970 <CGS> 223,612 <TOTAL-COSTS> 417,453 <OTHER-EXPENSES> (3,312) <LOSS-PROVISION> 0 <INTEREST-EXPENSE> 2,223 <INCOME-PRETAX> 72,606 <INCOME-TAX> 29,035 <INCOME-CONTINUING> 43,571 <DISCONTINUED> 0 <EXTRAORDINARY> 0 <CHANGES> 0 <NET-INCOME> 43,571 <EPS-PRIMARY> .54 <EPS-DILUTED> .54