| Year | Total | vs prev |
|---|---|---|
| 2013 | 0 | −100.0% |
| 2012 | 32 | −5.9% |
| 2011 | 34 | −45.2% |
| 2010 | 62 | −34.7% |
| 2009 | 95 | −43.8% |
| 2008 | 169 | +463.3% |
| 2007 | 30 | −63.9% |
| 2006 | 83 | +7.8% |
| 2005 | 77 | −38.4% |
| 2004 | 125 | −37.2% |
| 2003 | 199 | −21.7% |
| 2002 | 254 | −40.4% |
| 2001 | 426 | −43.5% |
| 2000 | 754 | −6.7% |
| 1999 | 808 | −19.1% |
| 1998 | 999 | — |