| Year | Count |
|---|---|
| 1947 | 6 |
| 1956 | 10 |
| 1960 | 5 |
| 1966 | 10 |
| 1967 | 18 |
| 1969 | 11 |
| 1970 | 13 |
| 1972 | 5 |
| 1973 | 19 |
| 1974 | 13 |
| 1975 | 19 |
| 1976 | 30 |
| 1977 | 36 |
| 1978 | 50 |
| 1979 | 43 |
| 1980 | 73 |
| 1981 | 71 |
| 1982 | 51 |
| 1983 | 19 |
| 1984 | 28 |
| 1985 | 70 |
| 1986 | 45 |
| 1987 | 29 |
| 1988 | 25 |
| 1989 | 11 |
| 1990 | 15 |
| 1991 | 6 |
| 1992 | 7 |
| 1993 | 7 |
| 1994 | 9 |
| 1995 | 8 |
| 1996 | 9 |
| 1997 | 20 |
| 1999 | 5 |
| 2000 | 5 |
| 2002 | 5 |