| Year | Count |
|---|---|
| 1955 | 15 |
| 1956 | 10 |
| 1957 | 6 |
| 1958 | 19 |
| 1959 | 20 |
| 1960 | 15 |
| 1961 | 8 |
| 1962 | 10 |
| 1963 | 8 |
| 1964 | 28 |
| 1965 | 15 |
| 1966 | 12 |
| 1967 | 10 |
| 1968 | 9 |
| 1969 | 20 |
| 1970 | 13 |
| 1971 | 39 |
| 1972 | 20 |
| 1973 | 16 |
| 1974 | 51 |
| 1975 | 15 |
| 1976 | 15 |
| 1977 | 6 |
| 1978 | 6 |
| 1979 | 23 |
| 1980 | 35 |
| 1981 | 39 |
| 1982 | 54 |
| 1983 | 55 |
| 1984 | 89 |
| 1985 | 50 |
| 1986 | 34 |
| 1987 | 12 |
| 1988 | 6 |
| 1989 | 10 |