| Year | Count |
|---|---|
| 1954 | 18 |
| 1956 | 5 |
| 1967 | 10 |
| 1969 | 25 |
| 1970 | 13 |
| 1971 | 19 |
| 1972 | 13 |
| 1973 | 11 |
| 1975 | 12 |
| 1976 | 10 |
| 1977 | 17 |
| 1978 | 23 |
| 1979 | 17 |
| 1980 | 22 |
| 1981 | 17 |
| 1983 | 17 |
| 1985 | 25 |
| 1986 | 45 |
| 1987 | 51 |
| 1988 | 59 |
| 1989 | 115 |
| 1990 | 105 |
| 1991 | 191 |
| 1992 | 190 |
| 1993 | 129 |
| 1994 | 161 |
| 1995 | 130 |
| 1996 | 154 |
| 1997 | 202 |
| 1998 | 235 |
| 1999 | 236 |
| 2000 | 205 |
| 2001 | 334 |
| 2002 | 239 |
| 2003 | 230 |
| 2004 | 289 |
| 2005 | 256 |
| 2006 | 257 |
| 2007 | 173 |
| 2008 | 218 |
| 2009 | 156 |
| 2010 | 125 |
| 2011 | 75 |
| 2012 | 89 |
| 2013 | 73 |
| 2014 | 65 |
| 2015 | 41 |
| 2016 | 18 |
| 2017 | 50 |
| 2018 | 19 |
| 2019 | 5 |
| 2020 | 15 |
| 2021 | 15 |
| 2023 | 8 |