| Year | Total | vs prev |
|---|---|---|
| 2017 | 0 | −100.0% |
| 2016 | 18 | −70.5% |
| 2015 | 61 | +15.1% |
| 2014 | 53 | −34.6% |
| 2013 | 81 | −9.0% |
| 2012 | 89 | −11.9% |
| 2011 | 101 | −49.2% |
| 2010 | 199 | +53.1% |
| 2009 | 130 | +62.5% |
| 2008 | 80 | +166.7% |
| 2007 | 30 | −14.3% |
| 2006 | 35 | −20.5% |
| 2005 | 44 | −43.6% |
| 2004 | 78 | −49.0% |
| 2003 | 153 | +10.9% |
| 2002 | 138 | −43.4% |
| 2001 | 244 | −8.6% |
| 2000 | 267 | −57.3% |
| 1997 | 626 | — |