<TABLE> <S> <C>
<PAGE>
<ARTICLE> 5
<MULTIPLIER> 1,000
<S> <C> <C>
<PERIOD-TYPE> 3-MOS 3-MOS
<FISCAL-YEAR-END> DEC-31-2000 DEC-31-1999
<PERIOD-START> JAN-01-2000 JAN-01-1999
<PERIOD-END> MAR-31-2000 MAR-31-1999
<CASH> 0 0
<SECURITIES> 0 0
<RECEIVABLES> 12,331 8,133
<ALLOWANCES> 0 0
<INVENTORY> 0 0
<CURRENT-ASSETS> 0 0
<PP&E> 968,087 881,360
<DEPRECIATION> 66,018 61,264
<TOTAL-ASSETS> 1,111,194 1,019,658
<CURRENT-LIABILITIES> 0 0
<BONDS> 0 0
0 0
20 20
<COMMON> 330 332
<OTHER-SE> 508,373 523,871
<TOTAL-LIABILITY-AND-EQUITY> 1,111,194 1,019,658
<SALES> 0 0
<TOTAL-REVENUES> 26,156 25,690
<CGS> 0 0
<TOTAL-COSTS> 0 0
<OTHER-EXPENSES> 14,021 11,239
<LOSS-PROVISION> 0 0
<INTEREST-EXPENSE> 5,742 3,977
<INCOME-PRETAX> 14,059 11,932
<INCOME-TAX> 0 0
<INCOME-CONTINUING> 14,059 11,932
<DISCONTINUED> 0 0
<EXTRAORDINARY> 0 0
<CHANGES> 0 0
<NET-INCOME> 12,887 10,760
<EPS-BASIC> $0.40 $0.33
<EPS-DILUTED> $0.40 $0.32
</TABLE>