<TABLE> <S> <C>

<PAGE>
<ARTICLE> 5
<MULTIPLIER> 1,000
       
<S>                             <C>                     <C>                     <C>
<PERIOD-TYPE>                   3-MOS                   6-MOS                   9-MOS
<FISCAL-YEAR-END>                          DEC-31-1996             DEC-31-1996             DEC-31-1996
<PERIOD-START>                             JAN-01-1996             JAN-01-1996             JAN-01-1996
<PERIOD-END>                               MAR-31-1996             JUN-30-1996             SEP-30-1996
<CASH>                                               6                       6                     239
<SECURITIES>                                    11,798                  12,507                   9,196
<RECEIVABLES>                                    6,858                   5,677                   4,513
<ALLOWANCES>                                       238                     209                     394
<INVENTORY>                                          0                       0                       0
<CURRENT-ASSETS>                                19,841                  19,538                  17,232
<PP&E>                                          26,273                  27,588                  28,674
<DEPRECIATION>                                  12,795                  13,247                  13,756
<TOTAL-ASSETS>                                  38,004                  39,010                  65,333
<CURRENT-LIABILITIES>                            4,758                   4,761                   8,930
<BONDS>                                              0                       0                       0
<PREFERRED-MANDATORY>                                0                       0                       0
<PREFERRED>                                          0                       0                       0
<COMMON>                                        21,119                  21,134                  21,303
<OTHER-SE>                                      11,632                  12,596                  13,702
<TOTAL-LIABILITY-AND-EQUITY>                    38,004                  39,010                  65,333
<SALES>                                         21,901                  44,276                  57,122
<TOTAL-REVENUES>                                21,901                  44,276                  57,122
<CGS>                                           17,435                  35,011                  42,474
<TOTAL-COSTS>                                   17,435                  35,011                  42,474
<OTHER-EXPENSES>                                 3,467                   7,055                  10,924
<LOSS-PROVISION>                                 (220)                   (538)                   (708)
<INTEREST-EXPENSE>                                   0                       0                       0
<INCOME-PRETAX>                                  1,219                   2,748                   4,432
<INCOME-TAX>                                       459                   1,061                   1,718
<INCOME-CONTINUING>                                  0                       0                   2,714
<DISCONTINUED>                                       0                       0                      89
<EXTRAORDINARY>                                      0                       0                       0
<CHANGES>                                            0                       0                       0
<NET-INCOME>                                       760                   1,687                   2,803
<EPS-PRIMARY>                                      .16                     .34                     .57
<EPS-DILUTED>                                      .16                     .34                     .57
        

</TABLE>