| Year | Count |
|---|---|
| 1970 | 6 |
| 1971 | 10 |
| 1971 | 5 |
| 1973 | 10 |
| 1973 | 6 |
| 1975 | 12 |
| 1976 | 25 |
| 1977 | 60 |
| 1977 | 6 |
| 1978 | 17 |
| 1979 | 10 |
| 1980 | 46 |
| 1981 | 20 |
| 1982 | 13 |
| 1983 | 7 |
| 1984 | 10 |
| 1985 | 23 |
| 1987 | 8 |
| 1988 | 11 |
| 1989 | 13 |
| 1990 | 29 |
| 1991 | 7 |
| 1992 | 8 |
| 1993 | 7 |
| 1994 | 6 |
| 1998 | 11 |
| 2003 | 5 |
| 2009 | 10 |
| 2009 | 6 |
| 2016 | 10 |
| 2020 | 7 |
| 2021 | 13 |