San Diego 91X posted their complete year-end countdowns for 1983-1995 on their webpage:
http://www.91x.com/
In case they move these lists off of their main page, try:
http://www.91x.com/top_91_1983.html
(replace 1983 with whatever year you want to look at)
It might be fun to compare these with KROQ's lists.