| Year | Count |
|---|---|
| 1980 | 10 |
| 1991 | 8 |
| 1994 | 14 |
| 1995 | 20 |
| 1997 | 29 |
| 1998 | 78 |
| 1999 | 124 |
| 2000 | 171 |
| 2001 | 282 |
| 2002 | 306 |
| 2003 | 472 |
| 2004 | 524 |
| 2005 | 601 |
| 2006 | 611 |
| 2007 | 484 |
| 2008 | 463 |
| 2009 | 359 |
| 2010 | 281 |
| 2011 | 177 |
| 2012 | 120 |
| 2013 | 78 |
| 2014 | 92 |
| 2015 | 60 |
| 2016 | 46 |
| 2017 | 21 |
| 2018 | 28 |
| 2020 | 7 |
| 2021 | 17 |
| 2022 | 10 |