| Year | Count |
|---|---|
| 1976 | 10 |
| 1977 | 12 |
| 1979 | 5 |
| 1983 | 6 |
| 1985 | 17 |
| 1986 | 16 |
| 1987 | 30 |
| 1988 | 38 |
| 1989 | 43 |
| 1990 | 85 |
| 1991 | 71 |
| 1992 | 104 |
| 1993 | 155 |
| 1994 | 136 |
| 1995 | 49 |
| 1996 | 106 |
| 1997 | 48 |
| 1998 | 50 |
| 1999 | 39 |
| 2000 | 34 |
| 2001 | 27 |
| 2002 | 37 |
| 2003 | 10 |
| 2004 | 10 |
| 2005 | 12 |
| 2007 | 12 |
| 2008 | 16 |
| 2009 | 10 |
| 2010 | 5 |
| 2012 | 10 |
| 2013 | 12 |
| 2014 | 14 |
| 2018 | 6 |
| 2021 | 14 |