<TABLE> <S> <C>

<PAGE>
<ARTICLE> 5
<RESTATED>

<S>                             <C>                     <C>                     <C>                     <C>
<PERIOD-TYPE>                   3-MOS                   6-MOS                   9-MOS                   12-MOS
<FISCAL-YEAR-END>                          DEC-31-1996             DEC-31-1996             DEC-31-1996              DEC-31-1995
<PERIOD-START>                             JAN-01-1996             JAN-01-1996             JAN-01-1996              JAN-01-1995
<PERIOD-END>                               MAR-31-1996             JUN-30-1996             SEP-30-1996              DEC-31-1995
<CASH>                                       1,121,452                  70,666               1,802,829                  751,606
<SECURITIES>                                         0                       0                       0                        0
<RECEIVABLES>                                2,398,788               3,254,719               3,422,664                2,721,698
<ALLOWANCES>                                 (263,861)               (256,883)               (262,135)                (250,140)
<INVENTORY>                                     85,724                  70,635                  70,894                   94,171
<CURRENT-ASSETS>                             4,909,476               5,439,564               7,147,748                5,272,443
<PP&E>                                      58,355,592              59,307,393              60,139,901               57,385,861
<DEPRECIATION>                              20,709,083              21,031,075              21,417,210               20,312,058
<TOTAL-ASSETS>                              45,165,077              46,335,274              48,035,915               45,294,758
<CURRENT-LIABILITIES>                        4,600,078               5,325,650               6,339,357                4,900,070
<BONDS>                                      6,023,000               6,005,000               5,988,000                7,273,335
<PREFERRED-MANDATORY>                                0                       0                       0                        0
<PREFERRED>                                          0                       0                       0                        0
<COMMON>                                     1,506,512               1,506,512               1,506,512                1,506,512
<OTHER-SE>                                  13,343,168              13,566,846              14,059,320               13,390,150
<TOTAL-LIABILITY-AND-EQUITY>                45,165,077              46,335,274              48,035,915               45,294,758
<SALES>                                      5,030,381              10,970,172              17,949,833               23,779,740
<TOTAL-REVENUES>                             5,225,268              11,581,189              18,985,561               25,486,322
<CGS>                                        1,615,230               3,748,330               6,247,752               13,116,905
<TOTAL-COSTS>                                4,244,114               9,172,059              14,760,425               20,101,015
<OTHER-EXPENSES>                                     0                       0                       0                        0
<LOSS-PROVISION>                                48,545                  49,648                  94,083                  155,206
<INTEREST-EXPENSE>                             172,024                 344,803                 516,808                  683,133
<INCOME-PRETAX>                                451,821               1,345,599               2,660,206                3,129,940
<INCOME-TAX>                                   181,352                 540,097               1,067,753                1,177,432
<INCOME-CONTINUING>                            270,469                 805,502               1,592,453                1,952,508
<DISCONTINUED>                                       0                       0                       0                        0
<EXTRAORDINARY>                                      0                       0                       0                        0
<CHANGES>                                            0                       0                       0                        0
<NET-INCOME>                                   270,469                 805,502               1,592,453                1,952,508
<EPS-PRIMARY>                                      .18                     .53                    1.05                     1.29
<EPS-DILUTED>                                      .18                     .53                    1.05                     1.29


</TABLE>