| Year | Count |
|---|---|
| 1955 | 6 |
| 1956 | 9 |
| 1957 | 26 |
| 1958 | 32 |
| 1959 | 30 |
| 1960 | 56 |
| 1961 | 80 |
| 1963 | 49 |
| 1964 | 39 |
| 1965 | 56 |
| 1966 | 73 |
| 1967 | 60 |
| 1968 | 44 |
| 1969 | 70 |
| 1970 | 96 |
| 1971 | 91 |
| 1972 | 78 |
| 1973 | 62 |
| 1974 | 52 |
| 1975 | 65 |
| 1976 | 43 |
| 1977 | 78 |
| 1978 | 82 |
| 1979 | 54 |
| 1980 | 40 |
| 1981 | 15 |
| 1982 | 19 |
| 1983 | 18 |
| 1984 | 10 |
| 1985 | 13 |
| 1986 | 16 |
| 1987 | 13 |
| 1988 | 18 |
| 1989 | 7 |
| 1990 | 11 |
| 1991 | 6 |
| 1992 | 16 |
| 1993 | 6 |
| 1997 | 5 |