<TABLE> <S> <C>
<PAGE>
<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THE
CONDENSED STATEMENTS OF INCOME AND THE CONDENSED BALANCE SHEETS AND IS
QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH FINANCIAL STATEMENTS.
</LEGEND>
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> DEC-31-2000
<PERIOD-START> JAN-01-2000
<PERIOD-END> JUN-30-2000
<CASH> 0
<SECURITIES> 0
<RECEIVABLES> 25,716,000
<ALLOWANCES> 0
<INVENTORY> 0
<CURRENT-ASSETS> 36,195,000
<PP&E> 220,696,000
<DEPRECIATION> 53,586,000
<TOTAL-ASSETS> 204,853,000
<CURRENT-LIABILITIES> 28,282,000
<BONDS> 82,121,000
0
0
<COMMON> 42,000
<OTHER-SE> 61,969,000
<TOTAL-LIABILITY-AND-EQUITY> 204,853,000
<SALES> 125,104,000
<TOTAL-REVENUES> 125,104,000
<CGS> 0
<TOTAL-COSTS> 115,847,000
<OTHER-EXPENSES> 0
<LOSS-PROVISION> 0
<INTEREST-EXPENSE> 2,808,000
<INCOME-PRETAX> 6,603,000
<INCOME-TAX> 2,509,000
<INCOME-CONTINUING> 4,094,000
<DISCONTINUED> 0
<EXTRAORDINARY> 0
<CHANGES> 0
<NET-INCOME> 4,094,000
<EPS-BASIC> 0.96
<EPS-DILUTED> 0.96
</TABLE>