| Year | Count |
|---|---|
| 1947 | 11 |
| 1948 | 6 |
| 1949 | 9 |
| 1950 | 13 |
| 1951 | 8 |
| 1952 | 15 |
| 1953 | 10 |
| 1954 | 11 |
| 1955 | 12 |
| 1956 | 12 |
| 1957 | 20 |
| 1958 | 46 |
| 1959 | 44 |
| 1960 | 24 |
| 1961 | 28 |
| 1963 | 18 |
| 1964 | 15 |
| 1965 | 14 |
| 1966 | 14 |
| 1967 | 12 |
| 1968 | 11 |
| 1969 | 21 |
| 1970 | 10 |
| 1971 | 7 |
| 1972 | 11 |
| 1973 | 11 |
| 1974 | 6 |
| 1976 | 14 |
| 1978 | 18 |
| 1981 | 5 |
| 1982 | 5 |
| 1987 | 5 |
| 1992 | 5 |
| 1994 | 5 |
| 1996 | 8 |
| 1997 | 6 |