| Year | Count |
|---|---|
| 1951 | 15 |
| 1952 | 5 |
| 1953 | 5 |
| 1954 | 20 |
| 1955 | 20 |
| 1956 | 5 |
| 1958 | 20 |
| 1959 | 5 |
| 1960 | 10 |
| 1963 | 20 |
| 1964 | 5 |
| 1965 | 49 |
| 1966 | 46 |
| 1967 | 43 |
| 1968 | 56 |
| 1969 | 74 |
| 1970 | 116 |
| 1971 | 163 |
| 1972 | 79 |
| 1973 | 76 |
| 1974 | 113 |
| 1975 | 148 |
| 1976 | 96 |
| 1977 | 125 |
| 1978 | 62 |
| 1979 | 30 |
| 1980 | 29 |
| 1981 | 37 |
| 1982 | 32 |
| 1983 | 6 |
| 1985 | 34 |
| 1986 | 6 |
| 1987 | 10 |
| 1988 | 13 |
| 1990 | 9 |
| 1991 | 6 |
| 1992 | 5 |
| 1993 | 7 |
| 1994 | 68 |
| 1995 | 36 |
| 1996 | 19 |