| Year | Total | vs prev |
|---|---|---|
| 2013 | 0 | −100.0% |
| 2012 | 69 | −4.2% |
| 2011 | 72 | −42.4% |
| 2010 | 125 | −17.8% |
| 2009 | 152 | −13.6% |
| 2008 | 176 | −13.3% |
| 2007 | 203 | +1930.0% |
| 2006 | 10 | −76.7% |
| 2005 | 43 | −65.9% |
| 2004 | 126 | −59.5% |
| 2003 | 311 | −41.1% |
| 2002 | 528 | −53.7% |
| 2001 | 1,141 | −39.6% |
| 2000 | 1,890 | +33.9% |
| 1999 | 1,411 | −26.5% |
| 1998 | 1,920 | +27.4% |
| 1997 | 1,507 | — |