| Year | Count |
|---|---|
| 1970 | 8 |
| 1971 | 12 |
| 1972 | 41 |
| 1973 | 33 |
| 1974 | 32 |
| 1975 | 67 |
| 1976 | 54 |
| 1977 | 66 |
| 1978 | 56 |
| 1979 | 70 |
| 1980 | 56 |
| 1981 | 40 |
| 1982 | 79 |
| 1983 | 50 |
| 1984 | 74 |
| 1985 | 64 |
| 1986 | 64 |
| 1987 | 33 |
| 1988 | 25 |
| 1989 | 54 |
| 1990 | 91 |
| 1991 | 83 |
| 1992 | 167 |
| 1993 | 142 |
| 1994 | 149 |
| 1995 | 252 |
| 1996 | 191 |
| 1997 | 129 |
| 1998 | 145 |
| 1999 | 136 |
| 2000 | 160 |
| 2001 | 161 |
| 2002 | 117 |
| 2003 | 71 |
| 2004 | 143 |
| 2005 | 68 |
| 2006 | 75 |
| 2007 | 60 |
| 2008 | 60 |
| 2009 | 25 |
| 2010 | 40 |
| 2011 | 55 |
| 2012 | 25 |
| 2013 | 48 |
| 2014 | 25 |
| 2015 | 13 |
| 2016 | 15 |
| 2017 | 24 |
| 2018 | 11 |
| 2019 | 15 |
| 2020 | 6 |
| 2021 | 16 |
| 2023 | 16 |
| 2024 | 5 |