| Year | Count |
|---|---|
| 1979 | 12 |
| 1981 | 5 |
| 1982 | 22 |
| 1983 | 5 |
| 1985 | 23 |
| 1986 | 6 |
| 1987 | 24 |
| 1988 | 30 |
| 1989 | 99 |
| 1990 | 56 |
| 1991 | 121 |
| 1992 | 132 |
| 1993 | 63 |
| 1994 | 127 |
| 1995 | 114 |
| 1996 | 107 |
| 1997 | 160 |
| 1998 | 224 |
| 1999 | 212 |
| 2000 | 223 |
| 2001 | 197 |
| 2002 | 144 |
| 2003 | 172 |
| 2004 | 174 |
| 2005 | 172 |
| 2006 | 192 |
| 2007 | 159 |
| 2008 | 92 |
| 2009 | 69 |
| 2010 | 55 |
| 2011 | 21 |
| 2012 | 5 |
| 2016 | 15 |