| Year | Count |
|---|---|
| 1977 | 5 |
| 1982 | 6 |
| 1987 | 10 |
| 1988 | 11 |
| 1989 | 5 |
| 1990 | 16 |
| 1991 | 6 |
| 1992 | 7 |
| 1993 | 30 |
| 1994 | 10 |
| 1997 | 5 |
| 1998 | 18 |
| 1999 | 42 |
| 2000 | 24 |
| 2001 | 11 |
| 2002 | 15 |
| 2003 | 10 |
| 2003 | 57 |
| 2004 | 72 |
| 2005 | 74 |
| 2006 | 41 |
| 2007 | 82 |
| 2008 | 68 |
| 2009 | 69 |
| 2010 | 46 |
| 2011 | 55 |
| 2012 | 5 |
| 2013 | 19 |
| 2014 | 29 |
| 2015 | 34 |
| 2016 | 35 |
| 2017 | 5 |
| 2018 | 39 |
| 2019 | 5 |
| 2020 | 5 |
| 2022 | 6 |