<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THE
CONDENSED CONSOLIDATED BALANCE SHEETS AND CONDENSED CONSOLIDATED STATEMENTS OF
INCOME AND NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS ON PAGES 1
THROUGH 19 OF THE COMPANY'S FORM 10-Q FOR THE SIX MONTH PERIOD ENDING JUNE 30,
2000, AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH FINANCIAL STATEMENTS

<MULTIPLIER> 1,000

                             
<PERIOD-TYPE>                   6-MOS
<FISCAL-YEAR-END>                          DEC-31-2000
<PERIOD-END>                               JUN-30-2000
<CASH>                                           6,286
<SECURITIES>                                         0
<RECEIVABLES>                                   78,711
<ALLOWANCES>                                         0
<INVENTORY>                                          0
<CURRENT-ASSETS>                                94,040
<PP&E>                                       2,228,035
<DEPRECIATION>                               1,512,498
<TOTAL-ASSETS>                                 839,344
<CURRENT-LIABILITIES>                           82,913
<BONDS>                                        395,676
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                          0
<COMMON>                                         5,412
<OTHER-SE>                                     331,239
<TOTAL-LIABILITY-AND-EQUITY>                   839,344
<SALES>                                        216,952
<TOTAL-REVENUES>                               216,952
<CGS>                                          121,060
<TOTAL-COSTS>                                  129,163
<OTHER-EXPENSES>                                50,582
<LOSS-PROVISION>                                     0
<INTEREST-EXPENSE>                              18,524
<INCOME-PRETAX>                                 18,683
<INCOME-TAX>                                     1,720
<INCOME-CONTINUING>                             16,963
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                    192
<CHANGES>                                            0
<NET-INCOME>                                    17,155
<EPS-BASIC>                                        .32
<EPS-DILUTED>                                      .32