| Year | Count |
|---|---|
| 1941 | 6 |
| 1942 | 5 |
| 1943 | 5 |
| 1946 | 5 |
| 1950 | 6 |
| 1955 | 6 |
| 1956 | 6 |
| 1957 | 9 |
| 1958 | 15 |
| 1959 | 16 |
| 1960 | 14 |
| 1961 | 8 |
| 1962 | 19 |
| 1963 | 24 |
| 1964 | 10 |
| 1965 | 9 |
| 1966 | 6 |
| 1969 | 9 |
| 1970 | 10 |
| 1971 | 12 |
| 1972 | 7 |
| 1985 | 5 |
| 1986 | 8 |
| 1987 | 7 |
| 1988 | 8 |
| 1990 | 8 |
| 1992 | 7 |
| 1997 | 7 |
| 1998 | 5 |
| 1999 | 6 |
| 2001 | 8 |
| 2003 | 8 |
| 2004 | 8 |
| 2005 | 7 |
| 2006 | 12 |
| 2007 | 27 |
| 2008 | 10 |
| 2009 | 10 |
| 2010 | 10 |
| 2011 | 13 |
| 2012 | 9 |
| 2013 | 12 |
| 2014 | 15 |
| 2015 | 11 |
| 2016 | 34 |
| 2017 | 16 |
| 2018 | 16 |
| 2019 | 8 |
| 2020 | 10 |
| 2021 | 5 |
| 2022 | 8 |
| 2023 | 7 |
| 2024 | 6 |