<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> 4,174 <SECURITIES> 139,293 <RECEIVABLES> 42,395 <ALLOWANCES> 1,270 <INVENTORY> 13,199 <CURRENT-ASSETS> 66,035 <PP&E> 248,471 <DEPRECIATION> 105,441 <TOTAL-ASSETS> 421,920 <CURRENT-LIABILITIES> 33,802 <BONDS> 51,964 <PREFERRED-MANDATORY> 0 <PREFERRED> 0 <COMMON> 10,677 <OTHER-SE> 255,403 <TOTAL-LIABILITY-AND-EQUITY> 421,920 <SALES> 120,222 <TOTAL-REVENUES> 122,140 <CGS> 76,395 <TOTAL-COSTS> 76,395 <OTHER-EXPENSES> 27,696 <LOSS-PROVISION> 448 <INTEREST-EXPENSE> 2,474 <INCOME-PRETAX> 15,127 <INCOME-TAX> 5,195 <INCOME-CONTINUING> 9,932 <DISCONTINUED> 0 <EXTRAORDINARY> 0 <CHANGES> 0 <NET-INCOME> 9,932 <EPS-PRIMARY> 1.16 <EPS-DILUTED> 1.16