| Year | Total | vs prev |
|---|---|---|
| 2010 | 0 | −100.0% |
| 2009 | 2 | +100.0% |
| 2008 | 1 | −98.1% |
| 2007 | 53 | −96.5% |
| 2006 | 1,510 | −29.2% |
| 2005 | 2,132 | +40.8% |
| 2004 | 1,514 | +5.4% |
| 2003 | 1,437 | −68.9% |
| 2002 | 4,624 | −38.6% |
| 2001 | 7,534 | −9.4% |
| 2000 | 8,317 | −13.2% |
| 1999 | 9,582 | +19.3% |
| 1998 | 8,029 | +195.9% |
| 1997 | 2,713 | — |