| Year | Count |
|---|---|
| 1951 | 5 |
| 1954 | 6 |
| 1955 | 6 |
| 1961 | 5 |
| 1962 | 6 |
| 1965 | 5 |
| 1966 | 5 |
| 1968 | 5 |
| 1972 | 10 |
| 1973 | 8 |
| 1975 | 7 |
| 1977 | 12 |
| 1981 | 5 |
| 1982 | 11 |
| 1983 | 7 |
| 1985 | 8 |
| 1986 | 6 |
| 1987 | 5 |
| 1988 | 9 |
| 1990 | 5 |
| 1991 | 6 |
| 1994 | 6 |
| 1998 | 6 |
| 2003 | 6 |
| 2005 | 6 |
| 2007 | 6 |
| 2009 | 8 |
| 2010 | 7 |
| 2011 | 8 |
| 2012 | 11 |
| 2013 | 9 |
| 2014 | 16 |
| 2015 | 45 |
| 2016 | 30 |
| 2017 | 27 |
| 2018 | 14 |
| 2019 | 28 |
| 2020 | 16 |
| 2021 | 30 |
| 2022 | 18 |
| 2023 | 24 |
| 2024 | 22 |