| Year | Count |
|---|---|
| 1972 | 14 |
| 1973 | 6 |
| 1974 | 9 |
| 1975 | 11 |
| 1976 | 17 |
| 1977 | 30 |
| 1978 | 24 |
| 1979 | 30 |
| 1981 | 12 |
| 1985 | 8 |
| 1987 | 6 |
| 1988 | 9 |
| 1990 | 11 |
| 1991 | 6 |
| 1992 | 8 |
| 1993 | 6 |
| 1996 | 8 |
| 2001 | 5 |
| 2005 | 7 |
| 2006 | 13 |
| 2007 | 6 |
| 2008 | 11 |
| 2009 | 12 |
| 2010 | 15 |
| 2011 | 13 |
| 2012 | 17 |
| 2013 | 14 |
| 2014 | 7 |
| 2015 | 24 |
| 2016 | 21 |
| 2017 | 18 |
| 2018 | 12 |
| 2019 | 14 |
| 2024 | 12 |