| Year | Count |
|---|---|
| 1967 | 10 |
| 1968 | 7 |
| 1970 | 6 |
| 1971 | 6 |
| 1972 | 9 |
| 1973 | 5 |
| 1974 | 10 |
| 1975 | 7 |
| 1976 | 8 |
| 1978 | 6 |
| 1979 | 5 |
| 1980 | 7 |
| 1981 | 10 |
| 1982 | 10 |
| 1983 | 21 |
| 1984 | 17 |
| 1989 | 17 |
| 1990 | 73 |
| 1990 | 5 |
| 1991 | 55 |
| 1991 | 5 |
| 1992 | 53 |
| 1992 | 6 |
| 1993 | 47 |
| 1993 | 5 |
| 1994 | 39 |
| 1995 | 18 |
| 1997 | 11 |
| 1998 | 5 |
| 1999 | 13 |
| 2000 | 13 |
| 2006 | 6 |