| Year | Count |
|---|---|
| 1975 | 6 |
| 1976 | 12 |
| 1979 | 10 |
| 1985 | 6 |
| 1987 | 8 |
| 1988 | 6 |
| 1989 | 12 |
| 1990 | 9 |
| 1991 | 9 |
| 1993 | 8 |
| 1994 | 5 |
| 1996 | 9 |
| 1997 | 8 |
| 1998 | 6 |
| 1999 | 5 |
| 2000 | 8 |
| 2002 | 6 |
| 2003 | 6 |
| 2004 | 9 |
| 2006 | 15 |
| 2007 | 28 |
| 2008 | 21 |
| 2009 | 21 |
| 2010 | 19 |
| 2011 | 19 |
| 2012 | 14 |
| 2013 | 18 |
| 2014 | 22 |
| 2015 | 27 |
| 2016 | 36 |
| 2017 | 21 |
| 2018 | 12 |
| 2020 | 12 |
| 2021 | 18 |
| 2022 | 10 |
| 2024 | 10 |