| Year | Count |
|---|---|
| 1963 | 10 |
| 1968 | 15 |
| 1969 | 19 |
| 1970 | 56 |
| 1971 | 73 |
| 1972 | 32 |
| 1973 | 67 |
| 1974 | 68 |
| 1975 | 112 |
| 1976 | 69 |
| 1977 | 124 |
| 1978 | 118 |
| 1979 | 98 |
| 1980 | 149 |
| 1981 | 105 |
| 1982 | 156 |
| 1983 | 143 |
| 1984 | 129 |
| 1985 | 130 |
| 1986 | 114 |
| 1987 | 119 |
| 1988 | 142 |
| 1989 | 231 |
| 1990 | 153 |
| 1991 | 201 |
| 1992 | 244 |
| 1993 | 157 |
| 1994 | 168 |
| 1995 | 187 |
| 1996 | 119 |
| 1997 | 88 |
| 1998 | 127 |
| 1999 | 57 |
| 2000 | 54 |
| 2001 | 102 |
| 2002 | 51 |
| 2003 | 41 |
| 2004 | 20 |
| 2005 | 18 |
| 2006 | 36 |
| 2007 | 39 |
| 2008 | 46 |
| 2009 | 11 |
| 2010 | 27 |
| 2012 | 18 |
| 2013 | 26 |
| 2014 | 16 |
| 2015 | 14 |
| 2016 | 14 |
| 2018 | 6 |
| 2021 | 6 |