| Year | Total | vs prev |
|---|---|---|
| 2017 | 0 | −100.0% |
| 2016 | 1 | −97.1% |
| 2015 | 35 | +133.3% |
| 2014 | 15 | −25.0% |
| 2013 | 20 | −57.4% |
| 2012 | 47 | +104.3% |
| 2011 | 23 | −74.2% |
| 2010 | 89 | +15.6% |
| 2009 | 77 | −36.9% |
| 2008 | 122 | −35.8% |
| 2007 | 190 | +630.8% |
| 2006 | 26 | −40.9% |
| 2005 | 44 | −27.9% |
| 2004 | 61 | +1.7% |
| 2003 | 60 | −55.9% |
| 2002 | 136 | −23.6% |
| 2001 | 178 | −23.6% |
| 2000 | 233 | −36.0% |
| 1999 | 364 | +167.6% |
| 1998 | 136 | — |