While not "Chicago" year-end charts, here is an interesting link to the top hits of 1970 - 2010 via Casey Kasem, et al.
Another link to flash back to even earlier years...
I remember "the top 100" airing on the former 99.9 WBUS-FM on New Year's Eve starting at 4pm and number one being played right around Midnight. First one I can recall listening to was around 1985, I believe.
Lots of nostalgia... when radio was...
Happy New Year to all of us radio/media junkies!