| Year | Count |
|---|---|
| 1980 | 10 |
| 1983 | 10 |
| 1984 | 10 |
| 1985 | 12 |
| 1986 | 22 |
| 1987 | 12 |
| 1988 | 16 |
| 1989 | 14 |
| 1990 | 34 |
| 1991 | 28 |
| 1992 | 48 |
| 1993 | 42 |
| 1994 | 26 |
| 1995 | 27 |
| 1996 | 25 |
| 1997 | 17 |
| 1998 | 28 |
| 1999 | 24 |
| 2000 | 33 |
| 2001 | 87 |
| 2002 | 42 |
| 2003 | 62 |
| 2004 | 25 |
| 2005 | 32 |
| 2006 | 26 |
| 2007 | 38 |
| 2008 | 44 |
| 2009 | 22 |
| 2010 | 18 |
| 2011 | 15 |
| 2012 | 12 |
| 2014 | 10 |
| 2016 | 10 |
| 2017 | 16 |