| Year | Count |
|---|---|
| 1931 | 11 |
| 1932 | 7 |
| 1933 | 15 |
| 1934 | 16 |
| 1935 | 17 |
| 1936 | 21 |
| 1937 | 17 |
| 1938 | 7 |
| 1939 | 7 |
| 1940 | 13 |
| 1941 | 10 |
| 1942 | 5 |
| 1943 | 5 |
| 1944 | 8 |
| 1946 | 5 |
| 1947 | 14 |
| 1948 | 14 |
| 1949 | 10 |
| 1950 | 8 |
| 1951 | 11 |
| 1952 | 8 |
| 1953 | 10 |
| 1954 | 20 |
| 1955 | 22 |
| 1956 | 10 |
| 1957 | 24 |
| 1958 | 28 |
| 1959 | 42 |
| 1960 | 18 |
| 1961 | 36 |
| 1963 | 19 |
| 1964 | 33 |
| 1965 | 21 |
| 1966 | 14 |
| 1967 | 19 |
| 1968 | 10 |
| 1969 | 10 |
| 1970 | 18 |
| 1971 | 11 |
| 1972 | 12 |
| 1973 | 8 |
| 1974 | 7 |
| 1975 | 5 |
| 1977 | 20 |
| 1978 | 22 |
| 1979 | 18 |
| 1981 | 5 |
| 1982 | 7 |
| 1986 | 5 |
| 1987 | 7 |
| 1990 | 6 |
| 1991 | 7 |
| 1992 | 7 |