<TABLE> <S> <C>

<PAGE>
<ARTICLE> 5
       
<S>                             <C>                     <C>
<PERIOD-TYPE>                   6-MOS                   6-MOS
<FISCAL-YEAR-END>                          DEC-31-1996             DEC-31-1997
<PERIOD-START>                             JAN-01-1996             JAN-01-1997
<PERIOD-END>                               JUN-30-1996             JUN-30-1997
<CASH>                                               0              18,433,500
<SECURITIES>                                         0              21,500,100
<RECEIVABLES>                                        0              12,088,500
<ALLOWANCES>                                         0                 477,300
<INVENTORY>                                          0                       0
<CURRENT-ASSETS>                                     0              60,192,400
<PP&E>                                               0              14,710,400
<DEPRECIATION>                                       0               6,203,900
<TOTAL-ASSETS>                                       0              68,759,200
<CURRENT-LIABILITIES>                                0              17,169,800
<BONDS>                                              0                       0
<PREFERRED-MANDATORY>                                0                       0
<PREFERRED>                                          0                       0
<COMMON>                                             0               1,422,200
<OTHER-SE>                                           0              46,600,900
<TOTAL-LIABILITY-AND-EQUITY>                         0              68,759,200
<SALES>                                              0                       0
<TOTAL-REVENUES>                            30,630,300              39,805,800
<CGS>                                                0                       0
<TOTAL-COSTS>                               22,579,600              27,685,800
<OTHER-EXPENSES>                             3,757,900               5,467,500
<LOSS-PROVISION>                                10,000                  95,000
<INTEREST-EXPENSE>                             201,900                 178,700
<INCOME-PRETAX>                              4,183,700               6,653,400
<INCOME-TAX>                                 1,673,000<F1>           2,661,300<F1>
<INCOME-CONTINUING>                          2,510,700<F1>           3,992,100<F1>
<DISCONTINUED>                                       0                       0
<EXTRAORDINARY>                                      0                       0
<CHANGES>                                            0                       0
<NET-INCOME>                                 2,510,700<F1>           3,992,100<F1>
<EPS-PRIMARY>                                      .19<F1>                 .30<F1>
<EPS-DILUTED>                                      .19<F1>                 .30<F1>
<FN>
<F1>INCOME TAXES, INCOME FROM CONTINUING OPERATIONS, NET INCOME AND EARNINGS PER
SHARE DATA INCLUDE PRO FORMA ADJUSTMENTS TO REFLECT A TOTAL PROVISION FOR INCOME
TAXES HAD THE CORPORATION BEEN TAXED AS A C CORPORATION FOR THE ENTIRE REPORTING
PERIOD.
</FN>
        

</TABLE>