| Year | Count |
|---|---|
| 1931 | 5 |
| 1955 | 5 |
| 1957 | 16 |
| 1958 | 10 |
| 1961 | 6 |
| 1973 | 8 |
| 1975 | 8 |
| 1977 | 10 |
| 1978 | 12 |
| 1979 | 14 |
| 1984 | 5 |
| 1990 | 6 |
| 1991 | 7 |
| 1992 | 6 |
| 1994 | 9 |
| 1995 | 5 |
| 1996 | 11 |
| 1997 | 9 |
| 1999 | 15 |
| 2000 | 9 |
| 2001 | 14 |
| 2003 | 9 |
| 2004 | 16 |
| 2005 | 17 |
| 2006 | 21 |
| 2007 | 18 |
| 2008 | 8 |
| 2009 | 11 |
| 2010 | 21 |
| 2011 | 11 |
| 2012 | 14 |
| 2013 | 11 |
| 2014 | 7 |
| 2015 | 21 |
| 2016 | 21 |
| 2018 | 16 |
| 2019 | 18 |
| 2020 | 24 |
| 2021 | 8 |
| 2022 | 18 |
| 2023 | 18 |