<TABLE> <S> <C>

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

<S>                             <C>                     <C>                     <C>                     <C>
<PERIOD-TYPE>                   12-MOS                   9-MOS                   6-MOS                   3-MOS
<FISCAL-YEAR-END>                          DEC-31-1999             DEC-31-1999             DEC-31-1999             DEC-31-1999
<PERIOD-END>                               DEC-31-1999             SEP-30-1999             JUN-30-1999             MAR-31-1999
<CASH>                                          40,600                  10,500                  20,600                  11,000
<SECURITIES>                                         0                       0                       0                       0
<RECEIVABLES>                                  217,400                 269,100                 235,700                  86,500
<ALLOWANCES>                                         0                       0                       0                       0
<INVENTORY>                                      7,000                  10,400                   7,200                   9,400
<CURRENT-ASSETS>                               307,100                 323,400                 280,100                 226,900
<PP&E>                                       6,287,900               6,261,200               6,179,300               6,300,900
<DEPRECIATION>                               3,967,700               4,035,100               3,974,000               4,064,300
<TOTAL-ASSETS>                               2,710,000               2,632,000               2,560,800               2,532,700
<CURRENT-LIABILITIES>                          342,900                 268,600                 228,400                 225,500
<BONDS>                                        975,000               1,067,700               1,248,000               1,276,100
<PREFERRED-MANDATORY>                                0                       0                       0                       0
<PREFERRED>                                          0                       0                       0                       0
<COMMON>                                         1,000                   1,000                   1,000                   1,000
<OTHER-SE>                                     805,000                 737,600                 669,200                 626,200
<TOTAL-LIABILITY-AND-EQUITY>                 2,710,000               2,632,000               2,560,800               2,532,700
<SALES>                                      1,895,100               1,314,800                 813,400                 353,800
<TOTAL-REVENUES>                             1,963,400               1,368,800                 855,700                 372,000
<CGS>                                          673,800                 505,400                 335,100                 172,600
<TOTAL-COSTS>                                  858,400                 628,800                 420,400                 211,600
<OTHER-EXPENSES>                               787,900                 531,600                 334,600                 132,600
<LOSS-PROVISION>                                     0                       0                       0                       0
<INTEREST-EXPENSE>                              77,300                  59,700                  40,100                  20,500
<INCOME-PRETAX>                                185,100                 109,900                  34,600                 (5,400)
<INCOME-TAX>                                  (28,000)                (28,500)                (32,700)                (24,400)
<INCOME-CONTINUING>                            213,100                 138,400                  67,300                  19,000
<DISCONTINUED>                                       0                       0                       0                       0
<EXTRAORDINARY>                                      0                       0                       0                       0
<CHANGES>                                            0                       0                       0                       0
<NET-INCOME>                                   213,100                 138,400                  67,300                  19,000
<EPS-BASIC>                                       2.19                    1.42                    0.69                    0.20
<EPS-DILUTED>                                     2.16                    1.40                    0.68                    0.19


</TABLE>