| Year | Count |
|---|---|
| 1982 | 8 |
| 1983 | 5 |
| 1986 | 5 |
| 1987 | 5 |
| 1988 | 17 |
| 1989 | 7 |
| 1990 | 11 |
| 1991 | 18 |
| 1992 | 11 |
| 1993 | 17 |
| 1994 | 23 |
| 1995 | 15 |
| 1996 | 15 |
| 1997 | 13 |
| 1998 | 11 |
| 1999 | 11 |
| 2000 | 13 |
| 2001 | 12 |
| 2002 | 7 |
| 2003 | 13 |
| 2004 | 7 |
| 2005 | 7 |
| 2006 | 12 |
| 2007 | 5 |
| 2009 | 5 |
| 2011 | 8 |
| 2012 | 8 |
| 2013 | 5 |
| 2014 | 8 |
| 2015 | 5 |
| 2016 | 7 |
| 2017 | 9 |
| 2018 | 5 |
| 2019 | 6 |