<TABLE> <S> <C>
<PAGE>
<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THE BALANCE
SHEETS OF THE COMPANY AS OF SEPTEMBER 30, 2000 (UNAUDITED) AND DECEMBER 31,
1999, STATEMENTS OF INCOME FOR THE PERIODS ENDED SEPTEMBER 30, 2000 AND 1999
(UNAUDITED) AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH FINANCIAL
STATEMENTS.
</LEGEND>
<S> <C> <C>
<PERIOD-TYPE> 9-MOS 9-MOS
<FISCAL-YEAR-END> DEC-31-2000 DEC-31-1999
<PERIOD-START> JAN-01-2000 JAN-01-1999
<PERIOD-END> SEP-30-2000 SEP-30-1999
<CASH> 4,935 13,313
<SECURITIES> 0 0
<RECEIVABLES> 38,345 31,167
<ALLOWANCES> 3,952 2,890
<INVENTORY> 0 0
<CURRENT-ASSETS> 0 0
<PP&E> 1,994,361 1,898,482
<DEPRECIATION> 116,703 91,461
<TOTAL-ASSETS> 2,096,896 1,994,663
<CURRENT-LIABILITIES> 0 0
<BONDS> 0 0
0 0
100,000 100,000
<COMMON> 405 401
<OTHER-SE> 705,410 731,092
<TOTAL-LIABILITY-AND-EQUITY> 2,096,896 1,994,663
<SALES> 0 0
<TOTAL-REVENUES> 250,809 221,983
<CGS> 0 0
<TOTAL-COSTS> 193,011 167,710
<OTHER-EXPENSES> 0 0
<LOSS-PROVISION> 0 0
<INTEREST-EXPENSE> 53,092 44,325
<INCOME-PRETAX> 53,040 50,852
<INCOME-TAX> 0 0
<INCOME-CONTINUING> 0 0
<DISCONTINUED> 0 0
<EXTRAORDINARY> 0 0
<CHANGES> 0 0
<NET-INCOME> 53,040 50,852
<EPS-BASIC> 1.32 1.21
<EPS-DILUTED> 1.31 1.21
</TABLE>