<TABLE> <S> <C>
<PAGE>
<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THE BALANCE
SHEETS OF THE COMPANY AS OF JUNE 30, 2000 (UNAUDITED) AND DECEMBER 31, 1999,
STATEMENTS OF INCOME FOR THE PERIODS ENDED JUNE 30, 2000 AND 1999 (UNAUDITED)
AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH FINANCIAL STATEMENTS.
</LEGEND>
<S> <C> <C>
<PERIOD-TYPE> 6-MOS 6-MOS
<FISCAL-YEAR-END> DEC-31-2000 DEC-31-1999
<PERIOD-START> JAN-01-2000 JAN-01-1999
<PERIOD-END> JUN-30-2000 JUN-30-1999
<CASH> 13,784 13,313
<SECURITIES> 0 0
<RECEIVABLES> 35,636 31,167
<ALLOWANCES> 3,916 2,890
<INVENTORY> 0 0
<CURRENT-ASSETS> 0 0
<PP&E> 1,881,653 1,898,482
<DEPRECIATION> 107,860 91,461
<TOTAL-ASSETS> 2,010,205 1,994,663
<CURRENT-LIABILITIES> 0 0
<BONDS> 0 0
0 0
100,000 100,000
<COMMON> 404 401
<OTHER-SE> 703,932 731,092
<TOTAL-LIABILITY-AND-EQUITY> 2,010,205 1,994,663
<SALES> 0 0
<TOTAL-REVENUES> 166,397 145,255
<CGS> 0 0
<TOTAL-COSTS> 127,824 108,737
<OTHER-EXPENSES> 0 0
<LOSS-PROVISION> 0 0
<INTEREST-EXPENSE> 35,156 28,607
<INCOME-PRETAX> 34,782 33,656
<INCOME-TAX> 0 0
<INCOME-CONTINUING> 0 0
<DISCONTINUED> 0 0
<EXTRAORDINARY> 0 0
<CHANGES> 0 0
<NET-INCOME> 34,782 33,656
<EPS-BASIC> .87 .80
<EPS-DILUTED> .86 .80
</TABLE>