| Year | Count |
|---|---|
| 1938 | 8 |
| 1939 | 21 |
| 1940 | 32 |
| 1941 | 19 |
| 1942 | 191 |
| 1943 | 192 |
| 1944 | 151 |
| 1945 | 156 |
| 1946 | 278 |
| 1947 | 375 |
| 1948 | 325 |
| 1949 | 228 |
| 1950 | 109 |
| 1951 | 100 |
| 1952 | 34 |
| 1953 | 78 |
| 1954 | 138 |
| 1955 | 224 |
| 1956 | 454 |
| 1957 | 1,020 |
| 1958 | 1,655 |
| 1959 | 2,090 |
| 1960 | 2,180 |
| 1961 | 2,251 |
| 1962 | 2,247 |
| 1963 | 2,367 |
| 1964 | 1,833 |
| 1965 | 1,289 |
| 1966 | 817 |
| 1967 | 748 |
| 1968 | 693 |
| 1969 | 584 |
| 1970 | 475 |
| 1971 | 369 |
| 1972 | 265 |
| 1973 | 197 |
| 1974 | 135 |
| 1975 | 76 |
| 1976 | 73 |
| 1977 | 33 |
| 1978 | 10 |
| 1979 | 54 |
| 1980 | 14 |
| 1981 | 28 |
| 1982 | 5 |
| 1983 | 5 |
| 1986 | 10 |
| 1991 | 6 |