| Year | Count |
|---|---|
| 1964 | 6 |
| 1968 | 6 |
| 1970 | 7 |
| 1971 | 10 |
| 1972 | 18 |
| 1973 | 9 |
| 1974 | 18 |
| 1976 | 24 |
| 1977 | 36 |
| 1978 | 26 |
| 1979 | 38 |
| 1980 | 10 |
| 1981 | 23 |
| 1982 | 5 |
| 1983 | 11 |
| 1984 | 15 |
| 1985 | 16 |
| 1987 | 7 |
| 1988 | 19 |
| 1989 | 5 |
| 1990 | 9 |
| 1991 | 6 |
| 1992 | 20 |
| 1994 | 18 |
| 1995 | 7 |
| 1997 | 7 |
| 2000 | 5 |
| 2001 | 6 |
| 2002 | 9 |
| 2004 | 10 |
| 2007 | 5 |
| 2008 | 10 |
| 2015 | 18 |
| 2016 | 18 |