| Year | Count |
|---|---|
| 1958 | 10 |
| 1966 | 8 |
| 1967 | 7 |
| 1969 | 7 |
| 1970 | 5 |
| 1972 | 6 |
| 1975 | 6 |
| 1977 | 14 |
| 1978 | 44 |
| 1979 | 18 |
| 1981 | 7 |
| 1982 | 10 |
| 1983 | 10 |
| 1984 | 11 |
| 1985 | 12 |
| 1986 | 11 |
| 1988 | 8 |
| 1989 | 9 |
| 1990 | 7 |
| 1991 | 12 |
| 1992 | 6 |
| 1993 | 7 |
| 1994 | 6 |
| 1995 | 7 |
| 1996 | 8 |
| 1997 | 6 |
| 1998 | 9 |
| 2004 | 5 |
| 2006 | 5 |
| 2009 | 7 |
| 2012 | 5 |
| 2013 | 7 |
| 2014 | 14 |
| 2015 | 18 |