| Year | Count |
|---|---|
| 1951 | 6 |
| 1969 | 5 |
| 1971 | 6 |
| 1973 | 6 |
| 1974 | 11 |
| 1975 | 8 |
| 1976 | 7 |
| 1978 | 8 |
| 1979 | 7 |
| 1980 | 17 |
| 1981 | 32 |
| 1982 | 22 |
| 1983 | 36 |
| 1984 | 27 |
| 1985 | 68 |
| 1986 | 76 |
| 1987 | 39 |
| 1988 | 43 |
| 1989 | 55 |
| 1990 | 89 |
| 1991 | 80 |
| 1992 | 128 |
| 1993 | 88 |
| 1994 | 123 |
| 1995 | 141 |
| 1996 | 92 |
| 1997 | 126 |
| 1998 | 121 |
| 1999 | 132 |
| 2000 | 195 |
| 2001 | 279 |
| 2002 | 176 |
| 2003 | 246 |
| 2004 | 241 |
| 2005 | 355 |
| 2006 | 404 |
| 2007 | 276 |
| 2008 | 361 |
| 2009 | 313 |
| 2010 | 221 |
| 2011 | 175 |
| 2012 | 300 |
| 2013 | 251 |
| 2014 | 193 |
| 2015 | 212 |
| 2016 | 241 |
| 2017 | 185 |
| 2018 | 192 |
| 2019 | 163 |
| 2020 | 96 |
| 2021 | 153 |
| 2022 | 204 |
| 2023 | 185 |
| 2024 | 170 |