| Year | Count |
|---|---|
| 1963 | 7 |
| 1966 | 5 |
| 1967 | 9 |
| 1969 | 8 |
| 1970 | 6 |
| 1971 | 5 |
| 1975 | 5 |
| 1982 | 5 |
| 1987 | 7 |
| 1988 | 7 |
| 1989 | 9 |
| 1990 | 12 |
| 1991 | 8 |
| 1992 | 10 |
| 1993 | 15 |
| 1994 | 17 |
| 1995 | 13 |
| 1996 | 13 |
| 1997 | 9 |
| 1998 | 19 |
| 1999 | 12 |
| 2000 | 16 |
| 2001 | 13 |
| 2002 | 15 |
| 2003 | 5 |
| 2004 | 12 |
| 2005 | 19 |
| 2006 | 18 |
| 2007 | 10 |
| 2008 | 10 |
| 2009 | 6 |
| 2010 | 12 |
| 2012 | 5 |
| 2016 | 21 |