| Year | Count |
|---|---|
| 1950 | 9 |
| 1953 | 6 |
| 1955 | 8 |
| 1957 | 14 |
| 1958 | 12 |
| 1959 | 20 |
| 1960 | 12 |
| 1961 | 22 |
| 1962 | 10 |
| 1963 | 9 |
| 1964 | 12 |
| 1965 | 12 |
| 1966 | 10 |
| 1967 | 8 |
| 1968 | 6 |
| 1969 | 9 |
| 1970 | 12 |
| 1971 | 8 |
| 1972 | 9 |
| 1973 | 7 |
| 1974 | 12 |
| 1975 | 12 |
| 1976 | 12 |
| 1977 | 28 |
| 1978 | 18 |
| 1979 | 26 |
| 1981 | 9 |
| 1983 | 8 |
| 1984 | 9 |
| 1985 | 7 |
| 1986 | 8 |
| 1987 | 9 |
| 1992 | 6 |
| 1997 | 5 |