| Year | Count |
|---|---|
| 1930 | 10 |
| 1934 | 27 |
| 1936 | 6 |
| 1937 | 28 |
| 1939 | 28 |
| 1940 | 10 |
| 1941 | 10 |
| 1942 | 26 |
| 1943 | 23 |
| 1944 | 22 |
| 1945 | 15 |
| 1946 | 69 |
| 1947 | 43 |
| 1948 | 36 |
| 1949 | 53 |
| 1950 | 85 |
| 1951 | 98 |
| 1952 | 111 |
| 1953 | 78 |
| 1954 | 133 |
| 1955 | 146 |
| 1956 | 123 |
| 1957 | 118 |
| 1958 | 100 |
| 1959 | 126 |
| 1960 | 149 |
| 1961 | 405 |
| 1962 | 310 |
| 1963 | 327 |
| 1964 | 389 |
| 1965 | 307 |
| 1966 | 269 |
| 1967 | 263 |
| 1968 | 174 |
| 1969 | 170 |
| 1970 | 126 |
| 1971 | 109 |
| 1972 | 73 |
| 1973 | 33 |
| 1974 | 81 |
| 1975 | 50 |
| 1976 | 19 |
| 1977 | 43 |
| 1978 | 23 |
| 1979 | 31 |
| 1980 | 44 |
| 1981 | 18 |
| 1982 | 23 |
| 1983 | 35 |
| 1984 | 18 |
| 1985 | 20 |
| 1986 | 17 |
| 1987 | 38 |
| 1988 | 14 |
| 1989 | 10 |
| 1990 | 17 |
| 1991 | 15 |
| 1992 | 5 |
| 1994 | 20 |
| 1995 | 5 |
| 1996 | 32 |
| 2000 | 12 |
| 2003 | 12 |
| 2004 | 10 |
| 2005 | 10 |