| Year | Count |
|---|---|
| 1947 | 5 |
| 1948 | 17 |
| 1949 | 14 |
| 1950 | 27 |
| 1951 | 35 |
| 1952 | 26 |
| 1953 | 29 |
| 1954 | 31 |
| 1955 | 41 |
| 1956 | 41 |
| 1957 | 70 |
| 1958 | 96 |
| 1959 | 92 |
| 1960 | 98 |
| 1961 | 132 |
| 1963 | 55 |
| 1964 | 59 |
| 1965 | 51 |
| 1966 | 40 |
| 1967 | 37 |
| 1968 | 47 |
| 1969 | 39 |
| 1970 | 39 |
| 1971 | 26 |
| 1972 | 24 |
| 1973 | 23 |
| 1974 | 18 |
| 1975 | 24 |
| 1976 | 19 |
| 1977 | 32 |
| 1978 | 38 |
| 1979 | 32 |
| 1981 | 13 |
| 1982 | 10 |
| 1983 | 8 |
| 1984 | 11 |
| 1985 | 7 |
| 1986 | 7 |
| 1987 | 8 |
| 1989 | 13 |
| 1990 | 6 |
| 1991 | 7 |
| 1992 | 9 |
| 1993 | 5 |