| Year | Count |
|---|---|
| 1967 | 5 |
| 1969 | 11 |
| 1970 | 12 |
| 1971 | 10 |
| 1972 | 9 |
| 1973 | 6 |
| 1974 | 11 |
| 1975 | 5 |
| 1977 | 24 |
| 1978 | 20 |
| 1979 | 14 |
| 1980 | 12 |
| 1981 | 9 |
| 1982 | 16 |
| 1983 | 18 |
| 1984 | 31 |
| 1985 | 28 |
| 1986 | 25 |
| 1987 | 20 |
| 1988 | 31 |
| 1989 | 29 |
| 1990 | 38 |
| 1991 | 48 |
| 1992 | 72 |
| 1993 | 55 |
| 1994 | 43 |
| 1995 | 54 |
| 1996 | 197 |
| 1997 | 133 |
| 1998 | 176 |
| 1999 | 125 |
| 2000 | 116 |
| 2001 | 173 |
| 2002 | 83 |
| 2003 | 83 |
| 2004 | 190 |
| 2005 | 173 |
| 2006 | 119 |
| 2007 | 70 |
| 2008 | 101 |
| 2009 | 70 |
| 2010 | 129 |
| 2011 | 72 |
| 2012 | 73 |
| 2013 | 36 |
| 2014 | 49 |
| 2015 | 79 |
| 2016 | 45 |
| 2017 | 37 |
| 2018 | 66 |
| 2019 | 59 |
| 2020 | 69 |
| 2021 | 24 |
| 2022 | 56 |
| 2023 | 52 |
| 2024 | 45 |