| Year | Total | vs prev |
|---|---|---|
| 2018 | 0 | −100.0% |
| 2017 | 16 | −79.7% |
| 2016 | 79 | −28.8% |
| 2015 | 111 | −33.1% |
| 2014 | 166 | +20.3% |
| 2013 | 138 | −52.4% |
| 2012 | 290 | +15.1% |
| 2011 | 252 | −25.9% |
| 2010 | 340 | −17.1% |
| 2009 | 410 | +12.9% |
| 2008 | 363 | −15.0% |
| 2007 | 427 | −9.1% |
| 2006 | 470 | −17.0% |
| 2005 | 566 | −8.3% |
| 2004 | 617 | −20.5% |
| 2003 | 776 | +4.9% |
| 2002 | 740 | +185.7% |
| 2001 | 259 | — |