| Year | Count |
|---|---|
| 1966 | 5 |
| 1967 | 6 |
| 1969 | 6 |
| 1970 | 9 |
| 1970 | 12 |
| 1971 | 11 |
| 1972 | 6 |
| 1972 | 8 |
| 1973 | 9 |
| 1973 | 20 |
| 1974 | 9 |
| 1974 | 17 |
| 1975 | 12 |
| 1975 | 26 |
| 1976 | 10 |
| 1976 | 17 |
| 1977 | 15 |
| 1978 | 20 |
| 1978 | 13 |
| 1979 | 15 |
| 1980 | 13 |
| 1981 | 9 |
| 1981 | 12 |
| 1982 | 7 |
| 1985 | 5 |
| 1988 | 7 |
| 1989 | 5 |
| 1990 | 6 |
| 1994 | 7 |
| 1995 | 5 |
| 1995 | 6 |
| 1996 | 7 |
| 1998 | 6 |
| 2000 | 7 |
| 2001 | 9 |
| 2002 | 5 |