| Year | Total | vs prev |
|---|---|---|
| 2019 | 0 | −100.0% |
| 2018 | 38 | −93.1% |
| 2017 | 551 | −42.2% |
| 2016 | 954 | −27.9% |
| 2015 | 1,324 | +8.7% |
| 2014 | 1,218 | +9.4% |
| 2013 | 1,113 | −23.8% |
| 2012 | 1,460 | −22.8% |
| 2011 | 1,892 | +10.3% |
| 2010 | 1,715 | +17.9% |
| 2009 | 1,455 | −11.3% |
| 2008 | 1,641 | −37.2% |
| 2007 | 2,611 | +139.5% |
| 2006 | 1,090 | +47.1% |
| 2005 | 741 | −26.7% |
| 2004 | 1,011 | −4.7% |
| 2003 | 1,061 | +73.6% |
| 2002 | 611 | +11.7% |
| 2001 | 547 | −32.0% |
| 2000 | 804 | +17.0% |
| 1999 | 687 | +28.7% |
| 1998 | 534 | +0.8% |
| 1997 | 530 | −12.7% |
| 1996 | 607 | −18.0% |
| 1995 | 740 | −15.8% |
| 1994 | 879 | +355.4% |
| 1993 | 193 | −49.9% |
| 1992 | 385 | +25.8% |
| 1991 | 306 | — |