<TABLE> <S> <C>
<PAGE>
<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM SEPTEMBER
30, 2000 FORM 10-Q AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH
FINANCIAL STATEMENTS.
</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> 14,181
<SECURITIES> 0
<RECEIVABLES> 136,967
<ALLOWANCES> 0
<INVENTORY> 0
<CURRENT-ASSETS> 170,852
<PP&E> 1,682,568
<DEPRECIATION> 640,542
<TOTAL-ASSETS> 1,258,193
<CURRENT-LIABILITIES> 193,629
<BONDS> 472,401
314
0
<COMMON> 0
<OTHER-SE> 557,304
<TOTAL-LIABILITY-AND-EQUITY> 1,258,193
<SALES> 574,224
<TOTAL-REVENUES> 550,436
<CGS> 213,813
<TOTAL-COSTS> 213,813
<OTHER-EXPENSES> 101,032
<LOSS-PROVISION> 0
<INTEREST-EXPENSE> 36,948
<INCOME-PRETAX> 198,643
<INCOME-TAX> 68,760
<INCOME-CONTINUING> 129,883
<DISCONTINUED> 0
<EXTRAORDINARY> 0
<CHANGES> 0
<NET-INCOME> 129,883
<EPS-BASIC> 2.08
<EPS-DILUTED> 2.03
</TABLE>