| Year | Count |
|---|---|
| 1956 | 5 |
| 1959 | 7 |
| 1960 | 5 |
| 1969 | 5 |
| 1970 | 5 |
| 1971 | 7 |
| 1973 | 6 |
| 1976 | 9 |
| 1977 | 5 |
| 1978 | 8 |
| 1985 | 5 |
| 1987 | 7 |
| 1989 | 6 |
| 1990 | 9 |
| 1991 | 9 |
| 1993 | 5 |
| 1994 | 9 |
| 1995 | 16 |
| 1996 | 18 |
| 1997 | 16 |
| 1998 | 6 |
| 1999 | 13 |
| 2000 | 12 |
| 2001 | 9 |
| 2002 | 19 |
| 2003 | 12 |
| 2004 | 13 |
| 2005 | 12 |
| 2006 | 24 |
| 2007 | 10 |
| 2008 | 21 |
| 2009 | 16 |
| 2010 | 17 |
| 2011 | 18 |
| 2012 | 14 |
| 2013 | 16 |
| 2014 | 10 |
| 2015 | 22 |
| 2018 | 44 |
| 2022 | 16 |