
<TABLE> <S> <C>

<PAGE>
<ARTICLE> 5
       
<S>                                        <C>                     <C>
<PERIOD-TYPE>                              6-MOS                   9-MOS
<FISCAL-YEAR-END>                          SEP-30-1997             SEP-30-1997
<PERIOD-START>                             OCT-01-1996             OCT-01-1996
<PERIOD-END>                               MAR-31-1997             JUN-30-1997
<CASH>                                          57,978                  21,745
<SECURITIES>                                         0                       0
<RECEIVABLES>                                   29,993                  16,414
<ALLOWANCES>                                         0                       0
<INVENTORY>                                      9,202                   8,691
<CURRENT-ASSETS>                               123,401                  72,856
<PP&E>                                         340,916                 348,324
<DEPRECIATION>                                       0                       0
<TOTAL-ASSETS>                                 857,054                 814,430
<CURRENT-LIABILITIES>                           84,505                  61,126
<BONDS>                                              0                       0
<PREFERRED-MANDATORY>                                0                       0
<PREFERRED>                                          0                       0
<COMMON>                                           200                     334
<OTHER-SE>                                     432,636                 421,599
<TOTAL-LIABILITY-AND-EQUITY>                   857,054                 814,430
<SALES>                                        260,178                 297,510
<TOTAL-REVENUES>                               260,178                 297,510
<CGS>                                                0                       0
<TOTAL-COSTS>                                  167,105                 222,043
<OTHER-EXPENSES>                                     0                       0
<LOSS-PROVISION>                                     0                       0
<INTEREST-EXPENSE>                              11,162                  15,853
<INCOME-PRETAX>                                 82,363                  60,771
<INCOME-TAX>                                    32,833                  24,551
<INCOME-CONTINUING>                             49,530                  36,220
<DISCONTINUED>                                       0                       0
<EXTRAORDINARY>                                      0                       0
<CHANGES>                                            0                       0
<NET-INCOME>                                    49,530                  36,220
<EPS-PRIMARY>                                     1.83                    1.23
<EPS-DILUTED>                                     1.83                    1.23
        

</TABLE>
