| Year | Count |
|---|---|
| 1968 | 6 |
| 1971 | 10 |
| 1972 | 5 |
| 1976 | 5 |
| 1977 | 27 |
| 1978 | 13 |
| 1979 | 26 |
| 1980 | 18 |
| 1981 | 44 |
| 1982 | 51 |
| 1983 | 78 |
| 1984 | 46 |
| 1985 | 79 |
| 1986 | 107 |
| 1987 | 111 |
| 1988 | 93 |
| 1989 | 105 |
| 1990 | 135 |
| 1991 | 173 |
| 1992 | 137 |
| 1993 | 134 |
| 1994 | 162 |
| 1995 | 100 |
| 1996 | 103 |
| 1997 | 114 |
| 1998 | 111 |
| 1999 | 78 |
| 2000 | 104 |
| 2001 | 186 |
| 2002 | 139 |
| 2003 | 122 |
| 2004 | 189 |
| 2005 | 185 |
| 2006 | 141 |
| 2007 | 123 |
| 2008 | 136 |
| 2009 | 87 |
| 2010 | 92 |
| 2011 | 58 |
| 2012 | 16 |
| 2013 | 28 |
| 2014 | 47 |
| 2015 | 65 |
| 2016 | 20 |
| 2017 | 31 |
| 2018 | 41 |
| 2019 | 48 |
| 2020 | 94 |
| 2021 | 79 |
| 2022 | 45 |
| 2023 | 55 |
| 2024 | 143 |