| Year | Count |
|---|---|
| 1973 | 5 |
| 1975 | 12 |
| 1979 | 6 |
| 1980 | 15 |
| 1981 | 5 |
| 1982 | 9 |
| 1983 | 7 |
| 1984 | 5 |
| 1986 | 20 |
| 1987 | 12 |
| 1988 | 17 |
| 1990 | 10 |
| 1991 | 32 |
| 1992 | 96 |
| 1993 | 28 |
| 1994 | 20 |
| 1995 | 5 |
| 1996 | 37 |
| 1997 | 41 |
| 1998 | 50 |
| 1999 | 25 |
| 2000 | 66 |
| 2001 | 52 |
| 2002 | 41 |
| 2003 | 55 |
| 2004 | 100 |
| 2005 | 53 |
| 2006 | 38 |
| 2007 | 25 |
| 2007 | 5 |
| 2008 | 29 |
| 2009 | 17 |
| 2010 | 6 |
| 2011 | 10 |
| 2012 | 5 |
| 2014 | 6 |
| 2016 | 5 |
| 2017 | 5 |
| 2020 | 5 |