<ARTICLE> 5
<MULTIPLIER> 1000
       
                             
<PERIOD-TYPE>                   3-MOS
<FISCAL-YEAR-END>                          DEC-31-1998
<PERIOD-END>                               MAR-31-1998
<CASH>                                         134,302
<SECURITIES>                                         0
<RECEIVABLES>                                  322,727
<ALLOWANCES>                                    (8,463)
<INVENTORY>                                      8,543
<CURRENT-ASSETS>                               520,680
<PP&E>                                       1,099,785
<DEPRECIATION>                                (725,384)
<TOTAL-ASSETS>                                 920,616
<CURRENT-LIABILITIES>                          397,676
<BONDS>                                         15,100
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                          0
<COMMON>                                        71,715
<OTHER-SE>                                     178,761
<TOTAL-LIABILITY-AND-EQUITY>                   920,616
<SALES>                                              0
<TOTAL-REVENUES>                               545,648
<CGS>                                                0
<TOTAL-COSTS>                                  530,848
<OTHER-EXPENSES>                                   481
<LOSS-PROVISION>                                     0
<INTEREST-EXPENSE>                                 995
<INCOME-PRETAX>                                 14,319
<INCOME-TAX>                                     7,302
<INCOME-CONTINUING>                              7,017
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                                     7,017
<EPS-PRIMARY>                                     0.30
<EPS-DILUTED>                                     0.29