| Year | Count |
|---|---|
| 1964 | 7 |
| 1965 | 6 |
| 1968 | 5 |
| 1971 | 5 |
| 1974 | 15 |
| 1975 | 13 |
| 1976 | 11 |
| 1977 | 16 |
| 1978 | 9 |
| 1979 | 6 |
| 1980 | 7 |
| 1981 | 15 |
| 1982 | 14 |
| 1983 | 5 |
| 1984 | 8 |
| 1985 | 15 |
| 1986 | 15 |
| 1987 | 21 |
| 1988 | 18 |
| 1989 | 18 |
| 1990 | 45 |
| 1991 | 35 |
| 1992 | 26 |
| 1993 | 54 |
| 1994 | 56 |
| 1995 | 75 |
| 1996 | 80 |
| 1997 | 113 |
| 1998 | 121 |
| 1999 | 157 |
| 2000 | 130 |
| 2001 | 131 |
| 2002 | 154 |
| 2003 | 190 |
| 2004 | 192 |
| 2005 | 223 |
| 2006 | 197 |
| 2007 | 230 |
| 2008 | 270 |
| 2009 | 240 |
| 2010 | 187 |
| 2011 | 224 |
| 2012 | 247 |
| 2013 | 187 |
| 2014 | 216 |
| 2015 | 171 |
| 2016 | 205 |
| 2017 | 163 |
| 2018 | 138 |
| 2019 | 148 |
| 2020 | 92 |
| 2021 | 94 |
| 2022 | 84 |
| 2023 | 106 |
| 2024 | 65 |