<TABLE> <S> <C>

<PAGE>
<ARTICLE> 5

<S>                             <C>                     <C>                     <C>                     <C>
<PERIOD-TYPE>                   YEAR                    3-MOS                   3-MOS                   3-MOS
<FISCAL-YEAR-END>                          DEC-31-1995             DEC-31-1996             DEC-31-1996             DEC-31-1996
<PERIOD-END>                               DEC-31-1995             MAR-31-1996             JUN-30-1996             SEP-30-1996
<CASH>                                          11,081                  13,119                  17,109                  18,091
<SECURITIES>                                     8,544                   9,256                  10,126                  12,248
<RECEIVABLES>                                   39,723                  48,244                  58,970                  74,865
<ALLOWANCES>                                     1,152                   1,354                   1,588                   1,864
<INVENTORY>                                          0                       0                       0                       0
<CURRENT-ASSETS>                                69,732                  78,743                  94,256                 113,419
<PP&E>                                          21,226                  22,984                  26,145                  30,658
<DEPRECIATION>                                   7,813                   8,014                   9,104                  11,427
<TOTAL-ASSETS>                                  88,172                  98,453                 116,582                 139,033
<CURRENT-LIABILITIES>                           32,499                  34,379                  40,152                  54,044
<BONDS>                                              0                       0                       0                       0
<PREFERRED-MANDATORY>                                0                       0                       0                       0
<PREFERRED>                                          0                       0                       0                       0
<COMMON>                                           489                     494                     504                     508
<OTHER-SE>                                           0                       0                       0                       0
<TOTAL-LIABILITY-AND-EQUITY>                    88,172                  98,453                 116,582                 139,033
<SALES>                                              0                       0                       0                       0
<TOTAL-REVENUES>                               179,667                  55,866                 121,207                 193,789
<CGS>                                                0                       0                       0                       0
<TOTAL-COSTS>                                  155,382                  46,887                 102,989                 165,471
<OTHER-EXPENSES>                               (1,818)                   (176)                   (488)                   (738)
<LOSS-PROVISION>                                   304                     250                     485                     758
<INTEREST-EXPENSE>                                 373                      17                      59                      69
<INCOME-PRETAX>                                 25,730                   9,138                  18,647                  28,987
<INCOME-TAX>                                    10,072                   3,714                   7,628                  11,880
<INCOME-CONTINUING>                             15,658                   5,424                  11,019                  17,107
<DISCONTINUED>                                       0                       0                       0                       0
<EXTRAORDINARY>                                      0                       0                       0                       0
<CHANGES>                                            0                       0                       0                       0
<NET-INCOME>                                    15,658                   5,424                   5,424                  17,107
<EPS-PRIMARY>                                     0.32                    0.11                    0.22                    0.34
<EPS-DILUTED>                                     0.28                    0.10                    0.20                    0.30



</TABLE>