| Year | Total | vs prev |
|---|---|---|
| 2005 | 0 | −100.0% |
| 2004 | 29 | −87.6% |
| 2003 | 233 | −23.9% |
| 2002 | 306 | −21.3% |
| 2001 | 389 | −17.8% |
| 2000 | 473 | −17.0% |
| 1999 | 570 | +3.6% |
| 1998 | 550 | −19.2% |
| 1997 | 681 | +121.1% |
| 1996 | 308 | −18.3% |
| 1995 | 377 | −25.2% |
| 1994 | 504 | −46.8% |
| 1993 | 947 | −16.6% |
| 1992 | 1,136 | +151.9% |
| 1991 | 451 | — |