<ARTICLE> 5 <MULTIPLIER> 1,000 <PERIOD-TYPE> 3-MOS <FISCAL-YEAR-END> DEC-31-1997 <PERIOD-END> MAR-31-1997 <CASH> 121,348 <SECURITIES> 7,967 <RECEIVABLES> 156,586 <ALLOWANCES> 0 <INVENTORY> 49,833 <CURRENT-ASSETS> 438,422 <PP&E> 899,191 <DEPRECIATION> 459,405 <TOTAL-ASSETS> 1,161,162 <CURRENT-LIABILITIES> 312,166 <BONDS> 0 <PREFERRED-MANDATORY> 0 <PREFERRED> 0 <COMMON> 82,163 <OTHER-SE> 644,063 <TOTAL-LIABILITY-AND-EQUITY> 1,161,162 <SALES> 466,476 <TOTAL-REVENUES> 466,476 <CGS> 204,296 <TOTAL-COSTS> 400,334 <OTHER-EXPENSES> (5,632) <LOSS-PROVISION> 0 <INTEREST-EXPENSE> 2,385 <INCOME-PRETAX> 69,389 <INCOME-TAX> 27,964 <INCOME-CONTINUING> 0 <DISCONTINUED> 0 <EXTRAORDINARY> 0 <CHANGES> 0 <NET-INCOME> 41,425 <EPS-PRIMARY> .50 <EPS-DILUTED> 0