| Year | Total | vs prev |
|---|---|---|
| 2019 | 0 | −100.0% |
| 2018 | 144 | −94.7% |
| 2017 | 2,701 | −29.5% |
| 2016 | 3,833 | −11.0% |
| 2015 | 4,306 | −16.6% |
| 2014 | 5,163 | −24.5% |
| 2013 | 6,839 | −24.6% |
| 2012 | 9,074 | +1.8% |
| 2011 | 8,915 | −24.2% |
| 2010 | 11,764 | −15.4% |
| 2009 | 13,910 | −28.9% |
| 2008 | 19,562 | −11.2% |
| 2007 | 22,036 | +552.0% |
| 2006 | 3,380 | — |