| Year | Count |
|---|---|
| 1938 | 31 |
| 1939 | 30 |
| 1940 | 162 |
| 1941 | 156 |
| 1942 | 299 |
| 1943 | 420 |
| 1944 | 448 |
| 1945 | 494 |
| 1946 | 588 |
| 1947 | 667 |
| 1948 | 318 |
| 1949 | 209 |
| 1950 | 134 |
| 1951 | 110 |
| 1952 | 92 |
| 1953 | 86 |
| 1954 | 59 |
| 1955 | 95 |
| 1956 | 103 |
| 1957 | 170 |
| 1958 | 300 |
| 1959 | 450 |
| 1960 | 483 |
| 1961 | 469 |
| 1962 | 276 |
| 1963 | 313 |
| 1964 | 265 |
| 1965 | 225 |
| 1966 | 207 |
| 1967 | 195 |
| 1968 | 118 |
| 1969 | 104 |
| 1970 | 79 |
| 1971 | 49 |
| 1972 | 30 |
| 1973 | 20 |
| 1974 | 10 |
| 1975 | 5 |
| 1976 | 10 |
| 1978 | 10 |
| 1980 | 6 |