<ARTICLE> 5 <MULTIPLIER> 1,000 <PERIOD-TYPE> 6-MOS <FISCAL-YEAR-END> DEC-31-1998 <PERIOD-END> JUN-30-1998 <CASH> 131,119 <SECURITIES> 278,111 <RECEIVABLES> 234,009 <ALLOWANCES> 2,548 <INVENTORY> 101,379 <CURRENT-ASSETS> 824,202 <PP&E> 1,766,754 <DEPRECIATION> 601,548 <TOTAL-ASSETS> 2,132,072 <CURRENT-LIABILITIES> 398,851 <BONDS> 0 <COMMON> 1,409 <PREFERRED-MANDATORY> 0 <PREFERRED> 0 <OTHER-SE> 1,615,082 <TOTAL-LIABILITY-AND-EQUITY> 2,132,072 <SALES> 654,951 <TOTAL-REVENUES> 654,951 <CGS> 358,951 <TOTAL-COSTS> 358,951 <OTHER-EXPENSES> 223,030 <LOSS-PROVISION> 0 <INTEREST-EXPENSE> 0 <INCOME-PRETAX> 83,355 <INCOME-TAX> 20,878 <INCOME-CONTINUING> 62,477 <DISCONTINUED> 0 <EXTRAORDINARY> 0 <CHANGES> 0 <NET-INCOME> 62,477 <EPS-PRIMARY> 0.44 <EPS-DILUTED> 0.44