<ARTICLE> 5
<LEGEND>
This  schedule  contains  summary  financial   information  extracted  from  the
consolidated  statement of earnings and the  consolidated  balance sheets and is
qualified in its entirety by reference to such financial statements.
</LEGEND>
<MULTIPLIER> 1,000
<CURRENCY> U.S. DOLLARS
       
                             
<PERIOD-TYPE>                   6-MOS
<FISCAL-YEAR-END>                          DEC-31-1997
<PERIOD-START>                             JAN-01-1997
<PERIOD-END>                               JUN-30-1997
<EXCHANGE-RATE>                                      1
<CASH>                                         170,087
<SECURITIES>                                         0
<RECEIVABLES>                                  113,811
<ALLOWANCES>                                    18,419
<INVENTORY>                                     43,064
<CURRENT-ASSETS>                               332,198
<PP&E>                                       1,466,529
<DEPRECIATION>                                 640,816
<TOTAL-ASSETS>                               1,317,403
<CURRENT-LIABILITIES>                          143,776
<BONDS>                                        345,084
<COMMON>                                        20,443
<PREFERRED-MANDATORY>                           29,309
<PREFERRED>                                          0
<OTHER-SE>                                     430,055
<TOTAL-LIABILITY-AND-EQUITY>                 1,317,403
<SALES>                                        452,281
<TOTAL-REVENUES>                               584,776
<CGS>                                          346,333
<TOTAL-COSTS>                                  457,160
<OTHER-EXPENSES>                                45,059
<LOSS-PROVISION>                                 9,658
<INTEREST-EXPENSE>                              17,325
<INCOME-PRETAX>                                 55,574
<INCOME-TAX>                                    18,313
<INCOME-CONTINUING>                             37,261
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                                    37,261
<EPS-PRIMARY>                                     1.82
<EPS-DILUTED>                                     1.82