| Year | N | Total Income | Average Income | Increase |
| 1989/90 | 56 | $64,506,118 | $1,151,895 | 13.9 |
| 1990/91 | 58 | $71,434,965 | $1,231,637 | 6.9 |
| 1991/92 | 57 | $72,676,597 | $1,275,028 | 3.5 |
| 1992/93 | 54 | $78,137,572 | $1,446,992 | 13.4 |
| 1993/94 | 54 | $80,892,348 | $1,498,006 | 3.5 |
| 1994/95 | 52 | $85,317,335 | $1,640,718 | 9.7 |
| 1995/96 | 56 | $95,698,167 | $1,708,896 | 4.0 |
| 1996/97 | 55 | $102,753,928 | $1,868,253 | 9.3 |
| 1997/98 | 56 | $110,853,934 | $1,979,535 | 7.9 |
| 1998/99 | 55 | $113,801,036 | $2,069,110 | 2.7 |