WARNING: THE EDGAR SYSTEM ENCOUNTERED ERROR(S) WHILE PROCESSING THIS SCHEDULE.

<TABLE> <S> <C>

<PAGE>

<ARTICLE> 5
<RESTATED>

<S>                                  <C>                     <C>                    <C>
<PERIOD-TYPE>                        12-MOS                  12-MOS                  12-MOS
<FISCAL-YEAR-END>                               DEC-31-1997            DEC-31-1996             DEC-31-1995
<PERIOD-START>                                  JAN-01-1997            JAN-01-1996             JAN-01-1995
<PERIOD-END>                                    DEC-31-1997            DEC-31-1996             DEC-31-1996
<CASH>                                               14,061                 12,327                  37,750
<SECURITIES>                                        101,826                101,065                  66,404
<RECEIVABLES>                                        67,855                 49,902                  34,758
<ALLOWANCES>                                        (1,268)                  (787)                   (592)
<INVENTORY>                                               0                      0                       0
<CURRENT-ASSETS>                                    197,193                169,750                 145,064
<PP&E>                                               55,649                 45,331                  37,238
<DEPRECIATION>                                       27,372                 23,098                  18,079
<TOTAL-ASSETS>                                      237,318                202,322                 169,517
<CURRENT-LIABILITIES>                                56,287                 37,850                  34,098
<BONDS>                                               2,500                  2,600                   2,907
<PREFERRED-MANDATORY>                                     0                      0                       0
<PREFERRED>                                               0                      0                       0
<COMMON>                                                260                    255                     247
<OTHER-SE>                                          176,344                158,295                 130,264
<TOTAL-LIABILITY-AND-EQUITY>                        237,318                202,322                 169,517
<SALES>                                              55,242                 48,513                  71,646
<TOTAL-REVENUES>                                    251,417                206,879                 175,285
<CGS>                                                40,422                 36,401                  46,743
<TOTAL-COSTS>                                       240,803                184,253                 141,818
<OTHER-EXPENSES>                                          0                      0                  14,429
<LOSS-PROVISION>                                        481                    430                     369
<INTEREST-EXPENSE>                                      197                    220                     292
<INCOME-PRETAX>                                      16,200                 27,508                  21,903
<INCOME-TAX>                                          8,238                 10,848                   1,230
<INCOME-CONTINUING>                                   7,962                 16,660                  20,673
<DISCONTINUED>                                            0                      0                       0
<EXTRAORDINARY>                                           0                      0                       0
<CHANGES>                                                 0                      0                       0
<NET-INCOME>                                          7,962                 16,660                  20,673
<EPS-PRIMARY>                                          0.31                   0.66                    0.73
<EPS-DILUTED>                                          0.30                   0.64                    0.63


</TABLE>