<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
<PREFERRED-MANDATORY>                                0                       0
<PREFERRED>                                    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>