Medium
| 2005 | January | June | ||
| 2004 | Summer | Winter | ||
| 2003 | Summer | Winter | ||
| 2002 | Summer | Winter | ||
| 2001 | Summer | Winter | ||
| 2000 | Summer | Winter | ||
| 1999 | Summer | Winter | ||
| 1998 | Spring | Summer - Fall | Winter | |
| 1997 | Spring | Summer | Fall | Winter |
| 1996 | Spring | Summer - Fall | Winter | |
| 1995 | Spring | Summer | Fall | Winter |
| 1994 | Spring | Summer | Fall | Winter |
| 1993 | Spring | Summer | Fall | Winter |
| 1992 | Summer | Winter | ||
| 1991 | June | December | ||
| 1990 | June | December | ||
| 1989 | June | December | ||
| 1988 | June | December | ||
| 1987 | June | December | ||
| 1986 | June | December | ||
| 1985 | June | December | ||
| 1984 | June | December | ||
| 1983 | June | December | ||
| 1982 | June | December | ||
| 1981 | June | December | ||
| 1980 | June | December | ||
| 1979 | June | December | ||
| 1978 | June | December | ||
| 1977 | June | December | ||
| 1976 | June | December | ||
| 1975 | June | December | ||
| 1974 | February | June | December |