<ARTICLE>                     5
       
                                                                    
<PERIOD-TYPE>                           3-MOS         6-MOS         9-MOS             12-MOS
<FISCAL-YEAR-END>                 DEC-31-1997   DEC-31-1997   DEC-31-1997        DEC-31-1997
<PERIOD-END>                      MAR-31-1997   JUN-30-1997   SEP-30-1997        DEC-31-1997
<CASH>                                $10,070       $ 8,908       $13,300            $12,334
<SECURITIES>                                0             0             0                  0
<RECEIVABLES>                          15,543        16,854        16,711             20,261
<ALLOWANCES>                              317           447           378                439
<INVENTORY>                                 0             0             0                  0
<CURRENT-ASSETS>                       25,836        26,081        30,071             32,981
<PP&E>                                 13,285        15,050        16,114             17,692
<DEPRECIATION>                          5,035         6,334         6,903              7,909
<TOTAL-ASSETS>                         76,569        79,204        85,335             90,805
<CURRENT-LIABILITIES>                   6,169         6,356         9,800             10,258
<BONDS>                                     0             0             0                  0
<PREFERRED-MANDATORY>                       0             0             0                  0
<PREFERRED>                                 0             0             0                  0
<COMMON>                                    0             0             0                  0
<OTHER-SE>                             66,994        69,527        72,327             76,317
<TOTAL-LIABILITY-AND-EQUITY>           76,569        79,204        85,334             90,805
<SALES>                                     0             0             0                  0
<TOTAL-REVENUES>                       18,621        38,810        60,707             84,590
<CGS>                                       0             0             0                  0
<TOTAL-COSTS>                           3,714        28,598        44,674             62,282
<OTHER-EXPENSES>                        2,163         4,497         7,045              9,705
<LOSS-PROVISION>                            0             0             0                  0
<INTEREST-EXPENSE>                         63           121           150                173
<INCOME-PRETAX>                         2,681         5,594         8,838             12,430
<INCOME-TAX>                            1,046         2,167         3,416              4,799
<INCOME-CONTINUING>                     1,635         3,427         5,422              7,631
<DISCONTINUED>                              0             0             0                  0
<EXTRAORDINARY>                             0             0             0                  0
<CHANGES>                                   0             0             0                  0
<NET-INCOME>                            1,635         3,427         5,422              7,631
<EPS-PRIMARY>                            0.16          0.33          0.52               0.73
<EPS-DILUTED>                            0.15          0.31          0.48               0.68