| Year | Total | vs prev |
|---|---|---|
| 2012 | 18 | −75.0% |
| 2011 | 72 | −26.5% |
| 2010 | 98 | −50.8% |
| 2009 | 199 | −51.0% |
| 2008 | 406 | +54.4% |
| 2007 | 263 | +29.6% |
| 2006 | 203 | −3.3% |
| 2005 | 210 | +165.8% |
| 2004 | 79 | +507.7% |
| 2003 | 13 | −62.9% |
| 2002 | 35 | −96.0% |
| 2001 | 881 | +19.5% |
| 2000 | 737 | −30.2% |
| 1999 | 1,056 | −5.8% |
| 1998 | 1,121 | — |