| Year | Count |
|---|---|
| 1971 | 11 |
| 1972 | 31 |
| 1973 | 20 |
| 1974 | 31 |
| 1975 | 34 |
| 1976 | 8 |
| 1977 | 30 |
| 1978 | 54 |
| 1979 | 33 |
| 1980 | 13 |
| 1981 | 38 |
| 1982 | 24 |
| 1983 | 32 |
| 1984 | 35 |
| 1985 | 89 |
| 1986 | 50 |
| 1987 | 185 |
| 1988 | 167 |
| 1989 | 127 |
| 1990 | 171 |
| 1991 | 188 |
| 1992 | 189 |
| 1993 | 186 |
| 1994 | 153 |
| 1995 | 118 |
| 1996 | 177 |
| 1997 | 162 |
| 1998 | 153 |
| 1999 | 129 |
| 2000 | 101 |
| 2001 | 123 |
| 2002 | 106 |
| 2003 | 97 |
| 2004 | 195 |
| 2005 | 207 |
| 2006 | 119 |
| 2007 | 133 |
| 2008 | 88 |
| 2009 | 43 |
| 2010 | 62 |
| 2011 | 40 |
| 2012 | 5 |
| 2013 | 6 |
| 2014 | 14 |
| 2015 | 17 |
| 2016 | 12 |
| 2017 | 9 |
| 2018 | 8 |
| 2019 | 6 |
| 2020 | 10 |
| 2022 | 20 |
| 2023 | 9 |
| 2024 | 10 |