| Year | Count |
|---|---|
| 1973 | 7 |
| 1975 | 6 |
| 1976 | 5 |
| 1977 | 12 |
| 1978 | 8 |
| 1979 | 6 |
| 1980 | 6 |
| 1981 | 7 |
| 1982 | 5 |
| 1983 | 5 |
| 1984 | 13 |
| 1985 | 11 |
| 1986 | 29 |
| 1987 | 5 |
| 1988 | 24 |
| 1989 | 18 |
| 1990 | 57 |
| 1991 | 83 |
| 1992 | 113 |
| 1993 | 83 |
| 1994 | 84 |
| 1995 | 87 |
| 1996 | 117 |
| 1997 | 74 |
| 1998 | 99 |
| 1999 | 46 |
| 2000 | 102 |
| 2001 | 116 |
| 2002 | 45 |
| 2003 | 83 |
| 2004 | 73 |
| 2005 | 87 |
| 2006 | 83 |
| 2007 | 50 |
| 2008 | 83 |
| 2009 | 99 |
| 2010 | 139 |
| 2011 | 137 |
| 2012 | 81 |
| 2013 | 43 |
| 2014 | 62 |
| 2015 | 48 |
| 2016 | 14 |
| 2017 | 42 |
| 2018 | 21 |
| 2019 | 17 |
| 2020 | 20 |
| 2022 | 10 |