| Year | Count |
|---|---|
| 1977 | 12 |
| 1983 | 5 |
| 1984 | 5 |
| 1985 | 9 |
| 1986 | 6 |
| 1987 | 11 |
| 1988 | 9 |
| 1989 | 12 |
| 1990 | 18 |
| 1991 | 17 |
| 1992 | 33 |
| 1993 | 46 |
| 1994 | 46 |
| 1995 | 44 |
| 1996 | 51 |
| 1997 | 50 |
| 1998 | 62 |
| 1999 | 51 |
| 2000 | 46 |
| 2001 | 42 |
| 2002 | 27 |
| 2003 | 39 |
| 2004 | 24 |
| 2005 | 23 |
| 2006 | 29 |
| 2007 | 19 |
| 2008 | 30 |
| 2009 | 24 |
| 2010 | 22 |
| 2011 | 11 |
| 2013 | 10 |
| 2014 | 7 |
| 2021 | 12 |