| Year | Count |
|---|---|
| 1950 | 5 |
| 1954 | 5 |
| 1958 | 7 |
| 1961 | 7 |
| 1962 | 5 |
| 1963 | 8 |
| 1965 | 7 |
| 1966 | 7 |
| 1968 | 6 |
| 1969 | 7 |
| 1970 | 10 |
| 1971 | 11 |
| 1973 | 24 |
| 1974 | 6 |
| 1975 | 5 |
| 1976 | 6 |
| 1977 | 44 |
| 1978 | 110 |
| 1979 | 105 |
| 1980 | 78 |
| 1981 | 55 |
| 1982 | 66 |
| 1983 | 60 |
| 1984 | 62 |
| 1985 | 37 |
| 1986 | 15 |
| 1987 | 44 |
| 1988 | 6 |
| 1989 | 10 |
| 1990 | 19 |
| 1991 | 5 |
| 1993 | 5 |
| 1994 | 6 |
| 1996 | 5 |
| 2000 | 5 |