<ARTICLE> 5 <MULTIPLIER> 1,000 <CURRENCY> U.S. DOLLARS <PERIOD-TYPE> 6-MOS <FISCAL-YEAR-END> DEC-31-1998 <PERIOD-START> JAN-01-1998 <PERIOD-END> JUN-30-1998 <EXCHANGE-RATE> 1 <CASH> 4,537 <SECURITIES> 0 <RECEIVABLES> 17,315 <ALLOWANCES> 0 <INVENTORY> 0 <CURRENT-ASSETS> 22,384 <PP&E> 303,906 <DEPRECIATION> 132,919 <TOTAL-ASSETS> 215,849 <CURRENT-LIABILITIES> 18,792 <BONDS> 26,615 <PREFERRED-MANDATORY> 0 <PREFERRED> 0 <COMMON> 110 <OTHER-SE> 150,559 <TOTAL-LIABILITY-AND-EQUITY> 215,849 <SALES> 39,258 <TOTAL-REVENUES> 39,446 <CGS> 8,116 <TOTAL-COSTS> 8,116 <OTHER-EXPENSES> 92 <LOSS-PROVISION> 0 <INTEREST-EXPENSE> 754 <INCOME-PRETAX> 5,602 <INCOME-TAX> 1,896 <INCOME-CONTINUING> 3,706 <DISCONTINUED> 34 <EXTRAORDINARY> 0 <CHANGES> 0 <NET-INCOME> 3,740 <EPS-PRIMARY> 0.34 <EPS-DILUTED> 0.33