| Year | Count |
|---|---|
| 1969 | 6 |
| 1970 | 7 |
| 1971 | 6 |
| 1975 | 5 |
| 1978 | 6 |
| 1979 | 5 |
| 1982 | 5 |
| 1984 | 7 |
| 1985 | 6 |
| 1986 | 11 |
| 1988 | 7 |
| 1989 | 11 |
| 1990 | 11 |
| 1991 | 28 |
| 1992 | 169 |
| 1993 | 181 |
| 1994 | 112 |
| 1995 | 138 |
| 1996 | 71 |
| 1997 | 73 |
| 1998 | 80 |
| 1999 | 105 |
| 2000 | 94 |
| 2001 | 93 |
| 2002 | 73 |
| 2003 | 44 |
| 2004 | 36 |
| 2005 | 35 |
| 2006 | 70 |
| 2007 | 65 |
| 2008 | 92 |
| 2009 | 103 |
| 2010 | 69 |
| 2011 | 20 |
| 2012 | 44 |
| 2013 | 49 |
| 2014 | 22 |
| 2015 | 32 |
| 2016 | 21 |
| 2017 | 36 |
| 2018 | 10 |
| 2019 | 25 |
| 2021 | 28 |
| 2022 | 8 |
| 2023 | 5 |
| 2024 | 12 |