| Year | Count |
|---|---|
| 1981 | 18 |
| 1982 | 19 |
| 1983 | 38 |
| 1984 | 52 |
| 1985 | 74 |
| 1986 | 65 |
| 1987 | 95 |
| 1988 | 91 |
| 1989 | 93 |
| 1990 | 91 |
| 1991 | 93 |
| 1992 | 76 |
| 1993 | 92 |
| 1994 | 86 |
| 1995 | 76 |
| 1996 | 86 |
| 1997 | 63 |
| 1998 | 47 |
| 1999 | 38 |
| 2000 | 33 |
| 2001 | 34 |
| 2002 | 32 |
| 2003 | 40 |
| 2004 | 82 |
| 2005 | 91 |
| 2006 | 55 |
| 2007 | 50 |
| 2008 | 36 |
| 2009 | 27 |
| 2010 | 23 |
| 2011 | 22 |
| 2012 | 11 |
| 2013 | 13 |
| 2014 | 9 |
| 2017 | 18 |