| Year | Count |
|---|---|
| 1971 | 8 |
| 1978 | 6 |
| 1981 | 7 |
| 1985 | 11 |
| 1987 | 5 |
| 1988 | 6 |
| 1989 | 11 |
| 1990 | 8 |
| 1991 | 13 |
| 1993 | 5 |
| 1994 | 18 |
| 1995 | 5 |
| 1996 | 29 |
| 1997 | 15 |
| 1998 | 36 |
| 1999 | 35 |
| 2000 | 30 |
| 2001 | 17 |
| 2002 | 13 |
| 2004 | 26 |
| 2005 | 11 |
| 2006 | 43 |
| 2007 | 5 |
| 2008 | 16 |
| 2009 | 36 |
| 2012 | 30 |
| 2014 | 32 |
| 2015 | 19 |
| 2016 | 29 |
| 2017 | 10 |
| 2018 | 19 |
| 2020 | 14 |
| 2021 | 5 |
| 2022 | 5 |
| 2024 | 8 |