| Year | Count |
|---|---|
| 1961 | 7 |
| 1963 | 5 |
| 1967 | 6 |
| 1968 | 7 |
| 1971 | 7 |
| 1972 | 7 |
| 1973 | 10 |
| 1974 | 5 |
| 1975 | 9 |
| 1976 | 10 |
| 1977 | 6 |
| 1978 | 14 |
| 1979 | 12 |
| 1980 | 16 |
| 1981 | 19 |
| 1982 | 11 |
| 1983 | 21 |
| 1984 | 23 |
| 1985 | 23 |
| 1986 | 22 |
| 1987 | 31 |
| 1988 | 21 |
| 1989 | 23 |
| 1990 | 34 |
| 1991 | 45 |
| 1992 | 29 |
| 1993 | 40 |
| 1994 | 35 |
| 1995 | 32 |
| 1996 | 41 |
| 1997 | 47 |
| 1998 | 45 |
| 1999 | 39 |
| 2000 | 35 |
| 2001 | 60 |
| 2002 | 55 |
| 2003 | 52 |
| 2004 | 80 |
| 2005 | 80 |
| 2006 | 97 |
| 2007 | 85 |
| 2008 | 96 |
| 2009 | 115 |
| 2010 | 120 |
| 2011 | 109 |
| 2012 | 84 |
| 2013 | 108 |
| 2014 | 108 |
| 2015 | 128 |
| 2016 | 189 |
| 2017 | 195 |
| 2018 | 220 |
| 2019 | 221 |
| 2020 | 154 |
| 2021 | 184 |
| 2022 | 175 |
| 2023 | 174 |
| 2024 | 161 |