| Year | Count |
|---|---|
| 1937 | 5 |
| 1938 | 10 |
| 1939 | 17 |
| 1940 | 24 |
| 1941 | 32 |
| 1942 | 48 |
| 1943 | 73 |
| 1944 | 94 |
| 1945 | 116 |
| 1946 | 156 |
| 1947 | 216 |
| 1948 | 196 |
| 1949 | 181 |
| 1950 | 208 |
| 1951 | 192 |
| 1952 | 277 |
| 1953 | 368 |
| 1954 | 488 |
| 1955 | 495 |
| 1956 | 423 |
| 1957 | 354 |
| 1958 | 338 |
| 1959 | 313 |
| 1960 | 270 |
| 1961 | 201 |
| 1962 | 193 |
| 1963 | 210 |
| 1964 | 166 |
| 1965 | 128 |
| 1966 | 81 |
| 1967 | 89 |
| 1968 | 112 |
| 1969 | 88 |
| 1970 | 54 |
| 1971 | 42 |
| 1972 | 46 |
| 1973 | 43 |
| 1974 | 15 |
| 1975 | 20 |
| 1976 | 16 |
| 1977 | 18 |
| 1978 | 10 |
| 1979 | 5 |
| 1982 | 5 |
| 1983 | 17 |
| 1985 | 5 |
| 1992 | 6 |
| 1996 | 5 |
| 1997 | 5 |
| 1998 | 5 |
| 1999 | 5 |
| 2006 | 5 |