| Year | Count |
|---|---|
| 1954 | 6 |
| 1958 | 7 |
| 1961 | 6 |
| 1962 | 8 |
| 1964 | 9 |
| 1966 | 11 |
| 1968 | 9 |
| 1970 | 11 |
| 1971 | 7 |
| 1972 | 8 |
| 1973 | 7 |
| 1976 | 5 |
| 1977 | 5 |
| 1978 | 5 |
| 1983 | 5 |
| 1984 | 7 |
| 1985 | 8 |
| 1989 | 7 |
| 1990 | 12 |
| 1991 | 13 |
| 1992 | 10 |
| 1993 | 12 |
| 1994 | 29 |
| 1995 | 16 |
| 1996 | 26 |
| 1997 | 30 |
| 1998 | 17 |
| 1999 | 19 |
| 2000 | 20 |
| 2001 | 19 |
| 2002 | 16 |
| 2003 | 26 |
| 2004 | 17 |
| 2005 | 11 |
| 2006 | 16 |
| 2007 | 8 |
| 2008 | 8 |
| 2009 | 10 |
| 2010 | 13 |
| 2012 | 5 |
| 2013 | 8 |
| 2015 | 10 |