<TABLE> <S> <C>

<PAGE>
<ARTICLE> 5
<RESTATED>
<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-START>                             JAN-01-1995             JAN-01-1996             JAN-01-1996             JAN-01-1996
             JAN-01-1996
<PERIOD-END>                               DEC-31-1995             DEC-31-1996             MAR-31-1996             JUN-30-1996
             SEP-30-1996
<CASH>                                           3,721                   2,468                   3,966                   3,814
                   4,820
<SECURITIES>                                    12,153                      76                   3,022                   1,726
                     450
<RECEIVABLES>                                   25,639                  27,309                  26,054                  28,578
                  25,942
<ALLOWANCES>                                     2,636                   2,330                   2,759                   3,302
                   3,105
<INVENTORY>                                     34,772                  50,451                  39,938                  47,098
                  48,643
<CURRENT-ASSETS>                                83,366                  91,700                  81,042                  90,404
                  90,137
<PP&E>                                         171,711                 220,489                 181,192                 188,920
                 200,313
<DEPRECIATION>                                  90,302                  96,644                  91,613                  92,551
                  95,316
<TOTAL-ASSETS>                                 182,332                 232,969                 187,729                 204,279
                 212,502
<CURRENT-LIABILITIES>                           50,636                  50,346                  49,515                  59,091
                  55,275
<BONDS>                                              0                       0                       0                       0
                       0
<PREFERRED-MANDATORY>                                0                       0                       0                       0
                       0
<PREFERRED>                                          0                       0                       0                       0
                       0
<COMMON>                                        52,974                  56,551                  54,710                  55,302
                  55,613
<OTHER-SE>                                      55,492                  87,557                  60,462                  69,093
                  76,598
<TOTAL-LIABILITY-AND-EQUITY>                   182,332                 232,969                 187,729                 204,279
                 212,502
<SALES>                                        253,900                 279,827                  68,301                 135,815
                 203,973
<TOTAL-REVENUES>                               255,355                 280,487                  68,301                 136,475
                 204,633
<CGS>                                          202,595                 213,007                  55,261                 104,952
                 158,792
<TOTAL-COSTS>                                   14,137                  15,033                   3,785                   7,632
                  11,176
<OTHER-EXPENSES>                                   146                   (236)                      50                    (31)
                   (120)
<LOSS-PROVISION>                                     0                       0                       0                       0
                       0
<INTEREST-EXPENSE>                                 562                     540                     130                     190
                     436
<INCOME-PRETAX>                                 38,944                  52,403                   9,194                  23,882
                  34,559
<INCOME-TAX>                                    14,397                  17,302                   3,011                   7,857
                  11,377
<INCOME-CONTINUING>                             24,547                  35,101                   6,183                  16,025
                  23,182
<DISCONTINUED>                                       0                       0                       0                       0
                       0
<EXTRAORDINARY>                                      0                       0                       0                       0
                       0
<CHANGES>                                            0                       0                       0                       0
                       0
<NET-INCOME>                                    24,547                  35,101                   6,183                  16,025
                  23,182
<EPS-PRIMARY>                                      .91                    1.29                     .23                     .59
                     .85
<EPS-DILUTED>                                      .87                    1.24                     .22                     .57
                     .82


</TABLE>