
<TABLE> <S> <C>

<PAGE>

<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THE
FINANCIAL STATEMENTS INCLUDED IN THE COMPANY'S QUARTERLY REPORT ON FORM 10-Q
ENDED MARCH 31, 1998 AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH
FINANCIAL STATEMENTS.
</LEGEND>
       
<S>                             <C>
<PERIOD-TYPE>                   6-MOS
<FISCAL-YEAR-END>                          SEP-30-1998
<PERIOD-START>                             OCT-01-1997
<PERIOD-END>                               MAR-31-1998
<CASH>                                     109,835,075
<SECURITIES>                                11,794,190
<RECEIVABLES>                               32,238,402
<ALLOWANCES>                                   317,000
<INVENTORY>                                          0
<CURRENT-ASSETS>                           174,452,874
<PP&E>                                      69,872,064
<DEPRECIATION>                              13,572,812
<TOTAL-ASSETS>                             268,065,355
<CURRENT-LIABILITIES>                       13,358,665
<BONDS>                                    144,340,146
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                          0
<COMMON>                                       260,551
<OTHER-SE>                                 102,015,993
<TOTAL-LIABILITY-AND-EQUITY>               268,065,355
<SALES>                                              0
<TOTAL-REVENUES>                            54,419,066
<CGS>                                                0
<TOTAL-COSTS>                               46,435,925
<OTHER-EXPENSES>                             (511,464)
<LOSS-PROVISION>                                     0
<INTEREST-EXPENSE>                           1,647,911
<INCOME-PRETAX>                              6,846,694
<INCOME-TAX>                                 2,599,603
<INCOME-CONTINUING>                          4,247,091
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                                 4,247,091
<EPS-PRIMARY>                                     0.17
<EPS-DILUTED>                                     0.16
        

</TABLE>
