| Year | Count |
|---|---|
| 1955 | 5 |
| 1959 | 7 |
| 1961 | 5 |
| 1962 | 10 |
| 1964 | 5 |
| 1965 | 11 |
| 1966 | 14 |
| 1967 | 15 |
| 1968 | 11 |
| 1969 | 6 |
| 1970 | 19 |
| 1971 | 53 |
| 1972 | 35 |
| 1973 | 44 |
| 1974 | 31 |
| 1975 | 22 |
| 1976 | 31 |
| 1977 | 16 |
| 1978 | 23 |
| 1979 | 24 |
| 1980 | 15 |
| 1981 | 27 |
| 1982 | 35 |
| 1983 | 31 |
| 1984 | 42 |
| 1985 | 92 |
| 1986 | 35 |
| 1987 | 32 |
| 1988 | 29 |
| 1989 | 37 |
| 1990 | 15 |
| 1991 | 11 |
| 1992 | 7 |
| 1995 | 5 |
| 1996 | 12 |
| 1999 | 5 |