| YEAR | Weighted Discharges |
|---|---|
| 2003 | 38,220,659 |
| 2002 | 37,804,021 |
| 2001 | 37,187,641 |
| 2000 | 36,417,565 |
| 1999 | 35,467,673 |
| 1998 | 34,874,001 |
| 1997 | 35,408,207 |
| 1996 | 34,874,386 |
| 1995 | 34,791,998 |
| 1994 | 34,622,203 |
| 1993 | 34,714,530 |
| 1992 | 35,011,385 |
| 1991 | 35,036,492 |
| 1990 | 35,215,397 |
| 1989 | 35,104,645 |
| 1988 | 35,171,448 |