| Year | Count |
|---|---|
| 1960 | 10 |
| 1966 | 5 |
| 1969 | 6 |
| 1972 | 13 |
| 1973 | 12 |
| 1974 | 7 |
| 1975 | 7 |
| 1976 | 11 |
| 1977 | 18 |
| 1977 | 11 |
| 1978 | 10 |
| 1978 | 7 |
| 1979 | 12 |
| 1979 | 12 |
| 1980 | 9 |
| 1982 | 5 |
| 1983 | 11 |
| 1985 | 7 |
| 1986 | 12 |
| 1987 | 5 |
| 1987 | 6 |
| 1988 | 11 |
| 1989 | 8 |
| 1990 | 11 |
| 1991 | 8 |
| 1992 | 11 |
| 1993 | 7 |
| 1994 | 6 |
| 1995 | 12 |
| 1996 | 8 |
| 1997 | 5 |
| 1998 | 8 |
| 2002 | 6 |
| 2003 | 5 |
| 2006 | 7 |
| 2013 | 8 |
| 2014 | 5 |
| 2018 | 12 |