| Year | Count |
|---|---|
| 1938 | 6 |
| 1940 | 15 |
| 1941 | 16 |
| 1942 | 53 |
| 1943 | 63 |
| 1944 | 33 |
| 1945 | 82 |
| 1946 | 165 |
| 1947 | 188 |
| 1948 | 138 |
| 1949 | 49 |
| 1950 | 47 |
| 1951 | 11 |
| 1952 | 39 |
| 1953 | 10 |
| 1954 | 24 |
| 1955 | 53 |
| 1956 | 93 |
| 1957 | 175 |
| 1958 | 289 |
| 1959 | 355 |
| 1960 | 365 |
| 1961 | 291 |
| 1962 | 288 |
| 1963 | 287 |
| 1964 | 396 |
| 1965 | 188 |
| 1966 | 248 |
| 1967 | 266 |
| 1968 | 253 |
| 1969 | 237 |
| 1970 | 316 |
| 1971 | 283 |
| 1972 | 235 |
| 1973 | 146 |
| 1974 | 159 |
| 1975 | 150 |
| 1976 | 105 |
| 1977 | 130 |
| 1978 | 140 |
| 1979 | 113 |
| 1980 | 90 |
| 1981 | 115 |
| 1982 | 85 |
| 1983 | 47 |
| 1984 | 76 |
| 1985 | 100 |
| 1986 | 64 |
| 1987 | 38 |
| 1988 | 42 |
| 1989 | 22 |
| 1991 | 12 |
| 1995 | 6 |
| 1997 | 11 |
| 2004 | 10 |