| Year | Total | vs prev |
|---|---|---|
| 2009 | 0 | −100.0% |
| 2008 | 2 | −97.4% |
| 2007 | 77 | +45.3% |
| 2006 | 53 | −64.9% |
| 2005 | 151 | −13.2% |
| 2004 | 174 | +19.2% |
| 2003 | 146 | +46.0% |
| 2002 | 100 | −32.9% |
| 2001 | 149 | −49.8% |
| 2000 | 297 | −7.2% |
| 1999 | 320 | −3.0% |
| 1998 | 330 | −21.2% |
| 1997 | 419 | −26.2% |
| 1996 | 568 | −30.4% |
| 1995 | 816 | +117.0% |
| 1994 | 376 | −30.9% |
| 1993 | 544 | −11.7% |
| 1992 | 616 | +34.2% |
| 1991 | 459 | — |