| Year | Count |
|---|---|
| 1963 | 10 |
| 1967 | 12 |
| 1968 | 5 |
| 1969 | 7 |
| 1970 | 17 |
| 1971 | 36 |
| 1972 | 34 |
| 1973 | 48 |
| 1974 | 13 |
| 1975 | 23 |
| 1976 | 15 |
| 1977 | 20 |
| 1978 | 32 |
| 1979 | 65 |
| 1980 | 133 |
| 1981 | 98 |
| 1982 | 104 |
| 1983 | 84 |
| 1984 | 44 |
| 1985 | 123 |
| 1986 | 69 |
| 1987 | 131 |
| 1988 | 95 |
| 1989 | 98 |
| 1990 | 151 |
| 1991 | 115 |
| 1992 | 87 |
| 1993 | 72 |
| 1994 | 58 |
| 1995 | 82 |
| 1996 | 27 |
| 1997 | 16 |
| 1998 | 27 |
| 1999 | 10 |
| 2000 | 16 |
| 2001 | 24 |
| 2003 | 12 |
| 2004 | 16 |
| 2005 | 23 |
| 2006 | 19 |
| 2007 | 39 |
| 2008 | 59 |
| 2009 | 15 |
| 2010 | 11 |
| 2011 | 22 |
| 2013 | 22 |
| 2014 | 5 |
| 2015 | 15 |
| 2016 | 14 |
| 2017 | 6 |
| 2018 | 7 |
| 2020 | 6 |
| 2021 | 16 |
| 2023 | 6 |