| Year | Count |
|---|---|
| 1920 | 6 |
| 1929 | 24 |
| 1931 | 5 |
| 1932 | 6 |
| 1933 | 7 |
| 1935 | 7 |
| 1936 | 13 |
| 1937 | 8 |
| 1938 | 11 |
| 1939 | 5 |
| 1940 | 9 |
| 1941 | 17 |
| 1942 | 13 |
| 1943 | 10 |
| 1944 | 9 |
| 1945 | 12 |
| 1946 | 29 |
| 1947 | 15 |
| 1948 | 24 |
| 1949 | 33 |
| 1950 | 47 |
| 1951 | 32 |
| 1952 | 49 |
| 1953 | 55 |
| 1954 | 63 |
| 1955 | 79 |
| 1956 | 83 |
| 1957 | 182 |
| 1958 | 150 |
| 1959 | 159 |
| 1960 | 141 |
| 1961 | 113 |
| 1962 | 28 |
| 1963 | 81 |
| 1964 | 66 |
| 1965 | 73 |
| 1966 | 57 |
| 1967 | 65 |
| 1968 | 58 |
| 1969 | 51 |
| 1970 | 76 |
| 1971 | 32 |
| 1972 | 61 |
| 1973 | 37 |
| 1974 | 37 |
| 1975 | 21 |
| 1976 | 27 |
| 1977 | 18 |
| 1978 | 51 |
| 1979 | 26 |
| 1980 | 12 |
| 1981 | 21 |
| 1982 | 5 |
| 1983 | 15 |
| 1984 | 23 |
| 1985 | 34 |
| 1986 | 15 |
| 1987 | 12 |
| 1988 | 6 |
| 1989 | 10 |
| 1990 | 5 |
| 1992 | 7 |
| 1994 | 6 |