| Year | Count |
|---|---|
| 1931 | 5 |
| 1933 | 10 |
| 1938 | 9 |
| 1939 | 5 |
| 1940 | 14 |
| 1943 | 6 |
| 1944 | 8 |
| 1946 | 10 |
| 1947 | 23 |
| 1948 | 5 |
| 1949 | 21 |
| 1950 | 28 |
| 1951 | 10 |
| 1952 | 42 |
| 1953 | 49 |
| 1954 | 30 |
| 1955 | 53 |
| 1956 | 123 |
| 1957 | 53 |
| 1958 | 87 |
| 1959 | 42 |
| 1960 | 75 |
| 1961 | 57 |
| 1962 | 77 |
| 1963 | 32 |
| 1964 | 12 |
| 1965 | 28 |
| 1966 | 10 |
| 1967 | 71 |
| 1968 | 9 |
| 1969 | 60 |
| 1970 | 34 |
| 1971 | 24 |
| 1972 | 26 |
| 1973 | 16 |
| 1974 | 15 |
| 1975 | 6 |
| 1976 | 18 |
| 1977 | 5 |
| 1978 | 11 |
| 1980 | 6 |
| 1982 | 6 |