<ARTICLE> 5 <MULTIPLIER> 1,000 <PERIOD-TYPE> 6-MOS <FISCAL-YEAR-END> DEC-31-1997 <PERIOD-END> JUN-30-1997 <CASH> 177,035 <SECURITIES> 558,946 <RECEIVABLES> 210,391 <ALLOWANCES> 3,154 <INVENTORY> 94,106 <CURRENT-ASSETS> 1,108,395 <PP&E> 1,516,531 <DEPRECIATION> 595,068 <TOTAL-ASSETS> 2,133,031 <CURRENT-LIABILITIES> 440,093 <BONDS> 0 <COMMON> 1,419 <PREFERRED-MANDATORY> 0 <PREFERRED> 0 <OTHER-SE> 1,553,098 <TOTAL-LIABILITY-AND-EQUITY> 2,133,031 <SALES> 640,392 <TOTAL-REVENUES> 640,392 <CGS> 333,119 <TOTAL-COSTS> 333,119 <OTHER-EXPENSES> 202,784 <LOSS-PROVISION> 0 <INTEREST-EXPENSE> 0 <INCOME-PRETAX> 117,072 <INCOME-TAX> 32,866 <INCOME-CONTINUING> 84,206 <DISCONTINUED> 0 <EXTRAORDINARY> 0 <CHANGES> 0 <NET-INCOME> 84,206 <EPS-PRIMARY> 0.62 <EPS-DILUTED> 0.59