| Year | Count |
|---|---|
| 1971 | 6 |
| 1978 | 8 |
| 1980 | 5 |
| 1982 | 8 |
| 1985 | 10 |
| 1986 | 10 |
| 1988 | 13 |
| 1989 | 5 |
| 1990 | 9 |
| 1994 | 5 |
| 1996 | 8 |
| 1998 | 22 |
| 1999 | 14 |
| 2000 | 14 |
| 2001 | 10 |
| 2002 | 20 |
| 2003 | 13 |
| 2004 | 31 |
| 2005 | 19 |
| 2006 | 10 |
| 2007 | 7 |
| 2008 | 11 |
| 2009 | 7 |
| 2011 | 6 |
| 2013 | 11 |
| 2017 | 12 |
| 2018 | 10 |
| 2019 | 5 |
| 2020 | 10 |
| 2022 | 10 |
| 2023 | 6 |
| 2024 | 5 |