| Year | Count |
|---|---|
| 1947 | 6 |
| 1949 | 5 |
| 1950 | 5 |
| 1951 | 7 |
| 1952 | 8 |
| 1953 | 10 |
| 1955 | 13 |
| 1956 | 16 |
| 1957 | 46 |
| 1958 | 38 |
| 1959 | 40 |
| 1960 | 28 |
| 1961 | 40 |
| 1963 | 22 |
| 1964 | 17 |
| 1965 | 22 |
| 1966 | 24 |
| 1967 | 11 |
| 1968 | 31 |
| 1969 | 18 |
| 1970 | 21 |
| 1971 | 27 |
| 1972 | 20 |
| 1973 | 9 |
| 1974 | 24 |
| 1975 | 6 |
| 1976 | 20 |
| 1977 | 31 |
| 1978 | 17 |
| 1979 | 17 |
| 1980 | 5 |
| 1983 | 19 |
| 1985 | 15 |
| 1988 | 10 |
| 1995 | 5 |
| 1996 | 6 |
| 1997 | 6 |
| 2004 | 10 |
| 2006 | 5 |
| 2007 | 7 |