| Year | Count |
|---|---|
| 1956 | 6 |
| 1957 | 10 |
| 1964 | 5 |
| 1965 | 6 |
| 1970 | 7 |
| 1971 | 9 |
| 1972 | 9 |
| 1973 | 8 |
| 1974 | 10 |
| 1977 | 14 |
| 1979 | 14 |
| 1981 | 7 |
| 1982 | 8 |
| 1983 | 5 |
| 1984 | 7 |
| 1985 | 7 |
| 1987 | 6 |
| 1988 | 8 |
| 1989 | 8 |
| 1990 | 12 |
| 1991 | 14 |
| 1992 | 9 |
| 1993 | 9 |
| 1994 | 11 |
| 1995 | 11 |
| 1997 | 5 |
| 1998 | 8 |
| 1999 | 6 |
| 2000 | 8 |
| 2001 | 6 |
| 2002 | 9 |
| 2003 | 6 |
| 2004 | 10 |
| 2005 | 11 |
| 2006 | 6 |
| 2007 | 6 |
| 2010 | 6 |