Colors are quite problematic: Hard to compare (which is "more red" or so), significant amount of people are color-blind to some degree. Aside of the aesthetic problems that easily occur.
Would it be a way out to use some sort of bar instead of the background color?
(could be implemented via a background color gradient which is shifted (and is many other ways))
The percentage is the primary data – color is used here just for as an additional cue.
Let's not start discussing redoing of the stats page here, that's better done in