<TABLE> <S> <C>

<ARTICLE> 5
<MULTIPLIER> 1,000
       
<S>                           <C>                     <C>                     <C>                <C>               <C>
<PERIOD-TYPE>                 YEAR                    YEAR                    3-MOS              6-MOS             9-MOS
<FISCAL-YEAR-END>             DEC-31-1995             DEC-31-1996             DEC-31-1996        DEC-31-1996       DEC-31-1996
<PERIOD-END>                  DEC-31-1995             DEC-31-1996             MAR-31-1996        JUN-30-1996       SEP-30-1996
<CASH>                            100,380                  73,052                 112,569            108,354            54,243
<SECURITIES>                            0                       0                       0                  0                 0
<RECEIVABLES>                      66,533                  82,586                  62,077             70,554            72,964   
<ALLOWANCES>                        2,009                   2,576                   2,192              2,099             2,451
<INVENTORY>                         6,190                   4,976                   4,987              4,871             6,268
<CURRENT-ASSETS>                  186,959                 172,140                 192,274            193,384           149,939
<PP&E>                            254,483                 305,350                 259,052            262,736           312,695
<DEPRECIATION>                    135,296                 149,418                 140,069            144,625           150,078
<TOTAL-ASSETS>                    495,073                 683,851                 501,741            501,726           671,069
<CURRENT-LIABILITIES>              58,106                  76,810                  58,548             57,281            78,718
<BONDS>                           114,500                 235,410                 114,500            100,000           235,410
<PREFERRED-MANDATORY>                   0                       0                       0                  0                 0      
<PREFERRED>                             0                       0                       0                  0                 0      
<COMMON>                              252                     337                     252                253               337  
<OTHER-SE>                        386,355                 437,456                 392,177            406,882           417,201
<TOTAL-LIABILITY-AND-EQUITY>      495,073                 683,851                 501,741            501,726           671,069
<SALES>                           472,327                 534,088                 115,706            243,280           382,145
<TOTAL-REVENUES>                  472,327                 534,088                 115,706            243,280           382,145
<CGS>                             190,013                 205,885                  49,209             98,774           152,881
<TOTAL-COSTS>                     190,013                 205,885                  49,209             98,774           152,881
<OTHER-EXPENSES>                   27,150                  31,102                   6,741             13,486            22,383 
<LOSS-PROVISION>                        0                       0                       0                  0                 0      
<INTEREST-EXPENSE>                 10,171                  13,592                   2,389              4,543             9,086  
<INCOME-PRETAX>                    79,368                  95,772                  16,837             43,407            65,338 
<INCOME-TAX>                       30,046                  38,272                   6,596             16,981            25,948 
<INCOME-CONTINUING>                49,322                  57,500                  10,241             26,426            39,390 
<DISCONTINUED>                          0                       0                       0                  0                 0      
<EXTRAORDINARY>                         0                       0                       0                  0                 0      
<CHANGES>                               0                       0                       0                  0                 0
<NET-INCOME>                       49,322                  57,500                  10,241             26,426            39,390 
<EPS-PRIMARY>                        2.26                    2.62                    0.47               1.21              1.80   
<EPS-DILUTED>                        2.23                    2.58                    0.46               1.19              1.77   
        


</TABLE>