| Year | Count |
|---|---|
| 1956 | 6 |
| 1958 | 12 |
| 1963 | 5 |
| 1965 | 19 |
| 1966 | 23 |
| 1967 | 37 |
| 1968 | 45 |
| 1969 | 69 |
| 1970 | 73 |
| 1971 | 45 |
| 1972 | 40 |
| 1973 | 29 |
| 1974 | 24 |
| 1975 | 29 |
| 1976 | 18 |
| 1977 | 38 |
| 1978 | 24 |
| 1979 | 28 |
| 1980 | 36 |
| 1981 | 18 |
| 1982 | 15 |
| 1983 | 14 |
| 1984 | 12 |
| 1985 | 15 |
| 1986 | 9 |
| 1987 | 11 |
| 1988 | 7 |
| 1989 | 13 |
| 1990 | 9 |
| 1991 | 7 |
| 1992 | 6 |
| 1994 | 5 |
| 1997 | 8 |
| 1998 | 5 |
| 2000 | 5 |