| Year | Count |
|---|---|
| 1973 | 6 |
| 1975 | 12 |
| 1976 | 18 |
| 1977 | 24 |
| 1978 | 37 |
| 1979 | 5 |
| 1979 | 39 |
| 1980 | 46 |
| 1981 | 57 |
| 1982 | 48 |
| 1983 | 53 |
| 1984 | 63 |
| 1985 | 48 |
| 1986 | 57 |
| 1987 | 49 |
| 1988 | 42 |
| 1989 | 73 |
| 1990 | 85 |
| 1991 | 127 |
| 1992 | 119 |
| 1993 | 142 |
| 1994 | 166 |
| 1995 | 220 |
| 1996 | 225 |
| 1997 | 157 |
| 1998 | 148 |
| 1999 | 145 |
| 2000 | 127 |
| 2001 | 114 |
| 2002 | 102 |
| 2003 | 90 |
| 2004 | 100 |
| 2005 | 120 |
| 2006 | 74 |
| 2007 | 61 |
| 2008 | 61 |
| 2009 | 14 |
| 2010 | 34 |
| 2011 | 30 |
| 2012 | 12 |
| 2013 | 17 |
| 2014 | 13 |
| 2015 | 37 |
| 2016 | 10 |
| 2017 | 7 |
| 2018 | 14 |
| 2019 | 7 |
| 2021 | 9 |
| 2022 | 6 |
| 2023 | 5 |
| 2024 | 5 |