| Year | Count |
|---|---|
| 1976 | 18 |
| 1977 | 20 |
| 1978 | 22 |
| 1979 | 12 |
| 1980 | 14 |
| 1981 | 24 |
| 1982 | 16 |
| 1983 | 40 |
| 1984 | 26 |
| 1985 | 28 |
| 1986 | 56 |
| 1987 | 41 |
| 1988 | 19 |
| 1989 | 18 |
| 1990 | 28 |
| 1991 | 11 |
| 1992 | 43 |
| 1993 | 45 |
| 1994 | 39 |
| 1995 | 48 |
| 1996 | 44 |
| 1997 | 58 |
| 1998 | 66 |
| 1999 | 92 |
| 2000 | 145 |
| 2001 | 163 |
| 2002 | 139 |
| 2003 | 118 |
| 2004 | 206 |
| 2005 | 178 |
| 2006 | 135 |
| 2007 | 126 |
| 2008 | 117 |
| 2009 | 97 |
| 2010 | 49 |
| 2011 | 43 |
| 2012 | 60 |
| 2013 | 11 |
| 2014 | 9 |
| 2015 | 11 |
| 2017 | 5 |
| 2023 | 5 |