<TABLE> <S> <C>

<ARTICLE> 5
<RESTATED>
<MULTIPLIER> 1,000

<S>                                        <C>                     <C>                     <C>                     <C>
<PERIOD-TYPE>                                3-MOS                   6-MOS                   9-MOS                   12-MOS
<FISCAL-YEAR-END>                          DEC-31-1996             DEC-31-1996             DEC-31-1996             DEC-31-1996
<PERIOD-END>                               MAR-31-1996             JUN-30-1996             SEP-30-1996             DEC-31-1996
<CASH>                                          33,334                  31,425                  18,015                  23,705
<SECURITIES>                                         0                       0                       0                       0
<RECEIVABLES>                                    8,519                   8,957                  10,276                  12,020
<ALLOWANCES>                                       121                     121                     121                     121
<INVENTORY>                                          0                       0                       0                       0
<CURRENT-ASSETS>                                44,286                  43,415                  31,334                  37,169
<PP&E>                                         239,705                 258,491                 275,431                 302,510
<DEPRECIATION>                                  75,419                  81,972                  89,063                  95,246
<TOTAL-ASSETS>                                 209,409                 220,797                 218,437                 245,757
<CURRENT-LIABILITIES>                           26,729                  28,663                  24,431                  32,325
<BONDS>                                         23,500                  29,719                  27,683                  42,000
<PREFERRED-MANDATORY>                                0                       0                       0                       0
<PREFERRED>                                          0                       0                       0                       0
<COMMON>                                           334                     334                     335                     334
<OTHER-SE>                                     158,846                 162,081                 165,988                 171,098
<TOTAL-LIABILITY-AND-EQUITY>                   209,409                 220,797                 218,437                 245,757
<SALES>                                         11,879                  24,637                  38,634                  55,123
<TOTAL-REVENUES>                                12,366                  25,510                  39,920                  56,733
<CGS>                                            6,316                  14,213                  22,896                  31,132
<TOTAL-COSTS>                                    6,316                  14,213                  22,896                  31,132
<OTHER-EXPENSES>                                     0                       0                       0                       0
<LOSS-PROVISION>                                     0                       0                       0                       0
<INTEREST-EXPENSE>                                 444                   1,043                   1,776                   2,582
<INCOME-PRETAX>                                  4,181                   7,404                  10,875                  16,666
<INCOME-TAX>                                      (26)                    (26)                    (26)                    (26)
<INCOME-CONTINUING>                              4,207                   7,430                  10,901                  16,692
<DISCONTINUED>                                       0                       0                       0                       0
<EXTRAORDINARY>                                      0                       0                       0                       0
<CHANGES>                                            0                       0                       0                       0
<NET-INCOME>                                     4,207                   7,430                  10,901                  16,692
<EPS-PRIMARY>                                     0.13                    0.23                    0.33                    0.50
<EPS-DILUTED>                                     0.12                    0.21                    0.24                    0.47


</TABLE>