| Year | Count |
|---|---|
| 1953 | 5 |
| 1954 | 15 |
| 1958 | 5 |
| 1959 | 10 |
| 1960 | 11 |
| 1961 | 26 |
| 1962 | 36 |
| 1963 | 42 |
| 1964 | 23 |
| 1965 | 35 |
| 1966 | 28 |
| 1967 | 66 |
| 1968 | 88 |
| 1969 | 89 |
| 1970 | 152 |
| 1971 | 184 |
| 1972 | 169 |
| 1973 | 205 |
| 1974 | 237 |
| 1975 | 209 |
| 1976 | 260 |
| 1977 | 224 |
| 1978 | 140 |
| 1979 | 139 |
| 1980 | 98 |
| 1981 | 115 |
| 1982 | 70 |
| 1983 | 72 |
| 1984 | 48 |
| 1985 | 65 |
| 1986 | 24 |
| 1987 | 26 |
| 1988 | 22 |
| 1989 | 21 |
| 1990 | 29 |
| 1991 | 20 |
| 1993 | 5 |