| Year | Count |
|---|---|
| 1971 | 22 |
| 1972 | 15 |
| 1973 | 7 |
| 1974 | 15 |
| 1975 | 42 |
| 1976 | 9 |
| 1977 | 48 |
| 1978 | 51 |
| 1979 | 52 |
| 1980 | 81 |
| 1981 | 66 |
| 1982 | 49 |
| 1983 | 67 |
| 1984 | 36 |
| 1985 | 44 |
| 1986 | 87 |
| 1987 | 114 |
| 1988 | 99 |
| 1989 | 237 |
| 1989 | 6 |
| 1990 | 199 |
| 1991 | 171 |
| 1992 | 246 |
| 1993 | 181 |
| 1994 | 227 |
| 1995 | 165 |
| 1996 | 232 |
| 1997 | 213 |
| 1998 | 285 |
| 1999 | 168 |
| 2000 | 215 |
| 2001 | 164 |
| 2002 | 139 |
| 2003 | 194 |
| 2004 | 190 |
| 2005 | 205 |
| 2006 | 162 |
| 2007 | 175 |
| 2008 | 192 |
| 2009 | 129 |
| 2010 | 149 |
| 2011 | 162 |
| 2012 | 149 |
| 2013 | 139 |
| 2014 | 150 |
| 2015 | 134 |
| 2016 | 176 |
| 2017 | 192 |
| 2018 | 164 |
| 2019 | 158 |
| 2020 | 91 |
| 2021 | 112 |
| 2022 | 91 |
| 2023 | 163 |
| 2024 | 179 |