| Year | Count |
|---|---|
| 1934 | 7 |
| 1949 | 5 |
| 1951 | 8 |
| 1952 | 10 |
| 1953 | 6 |
| 1954 | 6 |
| 1955 | 16 |
| 1956 | 14 |
| 1957 | 18 |
| 1958 | 27 |
| 1959 | 39 |
| 1960 | 44 |
| 1961 | 34 |
| 1962 | 70 |
| 1963 | 91 |
| 1964 | 71 |
| 1965 | 112 |
| 1966 | 151 |
| 1967 | 149 |
| 1968 | 216 |
| 1969 | 217 |
| 1970 | 268 |
| 1971 | 355 |
| 1972 | 391 |
| 1973 | 378 |
| 1974 | 449 |
| 1975 | 423 |
| 1976 | 438 |
| 1977 | 386 |
| 1978 | 359 |
| 1979 | 357 |
| 1980 | 295 |
| 1981 | 234 |
| 1982 | 214 |
| 1983 | 113 |
| 1984 | 93 |
| 1985 | 87 |
| 1986 | 86 |
| 1987 | 70 |
| 1988 | 104 |
| 1989 | 46 |
| 1990 | 71 |
| 1991 | 5 |
| 1992 | 5 |
| 1993 | 6 |