<ARTICLE> 5 <MULTIPLIER> 1,000 <PERIOD-TYPE> 6-MOS <FISCAL-YEAR-END> DEC-31-1998 <PERIOD-START> JAN-01-1998 <PERIOD-END> JUN-30-1998 <CASH> 141,017 <SECURITIES> 278,111 <RECEIVABLES> 239,302 <ALLOWANCES> 2,641 <INVENTORY> 106,073 <CURRENT-ASSETS> 846,425 <PP&E> 1,782,902 <DEPRECIATION> (610,890) <TOTAL-ASSETS> 2,163,950 <CURRENT-LIABILITIES> 404,727 <BONDS> 0 <PREFERRED-MANDATORY> 0 <PREFERRED> 0 <COMMON> 1,432 <OTHER-SE> 1,636,140 <TOTAL-LIABILITY-AND-EQUITY> 2,163,950 <SALES> 669,002 <TOTAL-REVENUES> 669,002 <CGS> 367,392 <TOTAL-COSTS> 367,392 <OTHER-EXPENSES> 231,230 <LOSS-PROVISION> 0 <INTEREST-EXPENSE> (175) <INCOME-PRETAX> 83,685 <INCOME-TAX> 20,890 <INCOME-CONTINUING> 62,795 <DISCONTINUED> 0 <EXTRAORDINARY> 0 <CHANGES> 0 <NET-INCOME> 62,795 <EPS-BASIC> 0.44 <EPS-DILUTED> 0.43