| Year | Count |
|---|---|
| 1978 | 10 |
| 1981 | 14 |
| 1982 | 13 |
| 1983 | 37 |
| 1984 | 32 |
| 1985 | 43 |
| 1986 | 45 |
| 1987 | 63 |
| 1988 | 52 |
| 1989 | 57 |
| 1990 | 76 |
| 1991 | 85 |
| 1992 | 70 |
| 1993 | 69 |
| 1994 | 70 |
| 1995 | 40 |
| 1996 | 46 |
| 1997 | 44 |
| 1998 | 35 |
| 1999 | 35 |
| 2000 | 38 |
| 2001 | 36 |
| 2002 | 40 |
| 2003 | 43 |
| 2004 | 33 |
| 2005 | 37 |
| 2006 | 19 |
| 2007 | 25 |
| 2008 | 16 |
| 2009 | 18 |
| 2010 | 11 |
| 2011 | 17 |
| 2012 | 10 |
| 2013 | 9 |
| 2014 | 6 |
| 2015 | 15 |
| 2016 | 21 |
| 2019 | 14 |