| Year | Count |
|---|---|
| 1958 | 10 |
| 1959 | 14 |
| 1960 | 22 |
| 1961 | 8 |
| 1963 | 17 |
| 1964 | 26 |
| 1965 | 37 |
| 1966 | 32 |
| 1967 | 36 |
| 1968 | 46 |
| 1969 | 50 |
| 1970 | 39 |
| 1971 | 47 |
| 1972 | 41 |
| 1973 | 48 |
| 1974 | 41 |
| 1975 | 29 |
| 1976 | 26 |
| 1977 | 56 |
| 1978 | 62 |
| 1979 | 66 |
| 1980 | 46 |
| 1981 | 19 |
| 1982 | 22 |
| 1983 | 17 |
| 1984 | 19 |
| 1985 | 19 |
| 1986 | 20 |
| 1987 | 22 |
| 1988 | 31 |
| 1989 | 28 |
| 1990 | 33 |
| 1991 | 21 |
| 1992 | 28 |
| 1993 | 20 |
| 1994 | 7 |
| 1995 | 9 |
| 1996 | 6 |