<ARTICLE> 5
<MULTIPLIER> 1,000
       
                                                             
<PERIOD-TYPE>                                    3-MOS                   9-MOS
<FISCAL-YEAR-END>                          DEC-31-1996             DEC-31-1996
<PERIOD-START>                             JUL-01-1996             JAN-01-1996
<PERIOD-END>                               SEP-30-1996             SEP-30-1996
<CASH>                                           9,446                   9,446
<SECURITIES>                                         0                       0
<RECEIVABLES>                                   38,680                  38,680
<ALLOWANCES>                                         0                       0
<INVENTORY>                                        962                     962
<CURRENT-ASSETS>                                49,974                  49,974
<PP&E>                                         602,957                 602,957
<DEPRECIATION>                                 180,789                 180,789
<TOTAL-ASSETS>                                 472,142                 472,142
<CURRENT-LIABILITIES>                           47,972                  47,972
<BONDS>                                              0                       0
<PREFERRED-MANDATORY>                                0                       0
<PREFERRED>                                          0                       0
<COMMON>                                           313                     313
<OTHER-SE>                                     363,262                 363,262
<TOTAL-LIABILITY-AND-EQUITY>                   472,142                 472,142
<SALES>                                         45,516                 132,959
<TOTAL-REVENUES>                                46,341                 136,053
<CGS>                                           19,455                  62,476
<TOTAL-COSTS>                                   31,050                  94,335
<OTHER-EXPENSES>                                 4,146                  11,212
<LOSS-PROVISION>                                     0                       0
<INTEREST-EXPENSE>                                  17                   3,154
<INCOME-PRETAX>                                 11,128                  27,352
<INCOME-TAX>                                     4,230                  10,393
<INCOME-CONTINUING>                              6,898                  16,959
<DISCONTINUED>                                       0                       0
<EXTRAORDINARY>                                      0                       0
<CHANGES>                                            0                       0
<NET-INCOME>                                     6,898                  16,959
<EPS-PRIMARY>                                      .22                     .62
<EPS-DILUTED>                                      .22                     .62