| Year | Count |
|---|---|
| 1940 | 5 |
| 1941 | 16 |
| 1942 | 97 |
| 1943 | 252 |
| 1944 | 240 |
| 1945 | 269 |
| 1946 | 488 |
| 1947 | 732 |
| 1948 | 630 |
| 1949 | 332 |
| 1950 | 250 |
| 1951 | 198 |
| 1952 | 172 |
| 1953 | 268 |
| 1954 | 365 |
| 1955 | 499 |
| 1956 | 1,017 |
| 1957 | 2,318 |
| 1958 | 3,791 |
| 1959 | 4,641 |
| 1960 | 4,437 |
| 1961 | 4,111 |
| 1962 | 3,916 |
| 1963 | 2,793 |
| 1964 | 2,315 |
| 1965 | 1,502 |
| 1966 | 1,046 |
| 1967 | 731 |
| 1968 | 632 |
| 1969 | 455 |
| 1970 | 333 |
| 1971 | 224 |
| 1972 | 173 |
| 1973 | 64 |
| 1974 | 28 |
| 1975 | 5 |
| 1982 | 6 |