| Year | Total | vs prev |
|---|---|---|
| 2008 | 0 | −100.0% |
| 2007 | 3 | −94.1% |
| 2006 | 51 | −95.2% |
| 2005 | 1,054 | −38.6% |
| 2004 | 1,718 | −19.2% |
| 2003 | 2,125 | −1.0% |
| 2002 | 2,147 | −19.3% |
| 2001 | 2,661 | −11.3% |
| 2000 | 3,001 | −3.8% |
| 1999 | 3,118 | −3.2% |
| 1998 | 3,222 | −37.2% |
| 1997 | 5,128 | +233.4% |
| 1996 | 1,538 | −44.0% |
| 1995 | 2,746 | −20.1% |
| 1994 | 3,437 | −26.1% |
| 1993 | 4,654 | −12.3% |
| 1992 | 5,306 | +212.3% |
| 1991 | 1,699 | — |