<TABLE> <S> <C>
<PAGE>
<ARTICLE> 5
<LEGEND>
THE CONSOLIDATED FINANCIAL STATEMENTS OF THE REGISTRANT FOR THE QUARTER ENDED
SEPTEMBER 30, 2000.
</LEGEND>
<MULTIPLIER> 1,000
<S> <C>
<PERIOD-TYPE> 9-MOS
<FISCAL-YEAR-END> DEC-31-2000
<PERIOD-START> JAN-01-2000
<PERIOD-END> SEP-30-2000
<CASH> 2,640
<SECURITIES> 0
<RECEIVABLES> 26,761
<ALLOWANCES> 0
<INVENTORY> 1,228
<CURRENT-ASSETS> 33,349
<PP&E> 500,747
<DEPRECIATION> 381,330
<TOTAL-ASSETS> 153,021
<CURRENT-LIABILITIES> 41,085
<BONDS> 27,000
0
0
<COMMON> 925
<OTHER-SE> 82,591
<TOTAL-LIABILITY-AND-EQUITY> 153,021
<SALES> 74,397
<TOTAL-REVENUES> 78,994
<CGS> 13,224
<TOTAL-COSTS> 51,114<F1>
<OTHER-EXPENSES> (1,199)
<LOSS-PROVISION> 0
<INTEREST-EXPENSE> 1,815
<INCOME-PRETAX> 27,264
<INCOME-TAX> 1,585
<INCOME-CONTINUING> 25,679
<DISCONTINUED> 0
<EXTRAORDINARY> 0
<CHANGES> 0
<NET-INCOME> 25,679
<EPS-BASIC> 2.79
<EPS-DILUTED> 2.70
<FN>
<F1>Includes $2,221 charge for stock-based employee compensation.
</FN>
</TABLE>