<ARTICLE> 5 <MULTIPLIER> 1,000 <PERIOD-TYPE> 3-MOS <FISCAL-YEAR-END> DEC-31-1997 <PERIOD-START> JAN-01-1997 <PERIOD-END> MAR-31-1997 <CASH> 214,377 <SECURITIES> 544,210 <RECEIVABLES> 189,589 <ALLOWANCES> 3,961 <INVENTORY> 80,723 <CURRENT-ASSETS> 1,094,446 <PP&E> 1,347,137 <DEPRECIATION> 543,713 <TOTAL-ASSETS> 1,991,237 <CURRENT-LIABILITIES> 344,164 <BONDS> 0 <PREFERRED-MANDATORY> 0 <PREFERRED> 0 <COMMON> 1,411 <OTHER-SE> 1,472,825 <TOTAL-LIABILITY-AND-EQUITY> 1,991,237 <SALES> 308,388 <TOTAL-REVENUES> 308,388 <CGS> 164,120 <TOTAL-COSTS> 164,120 <OTHER-EXPENSES> 95,442 <LOSS-PROVISION> 0 <INTEREST-EXPENSE> 1,497 <INCOME-PRETAX> 53,416 <INCOME-TAX> 15,009 <INCOME-CONTINUING> 38,407 <DISCONTINUED> 0 <EXTRAORDINARY> 0 <CHANGES> 0 <NET-INCOME> 38,407 <EPS-PRIMARY> 0.30 <EPS-DILUTED> 0.28