As @jasonstevanhill has mentioned before downloads for iOS are meant to be more than half of the total sales for CoG/HG. I find it curious that it is android users who are more likely to rate/review the games.
For example Unnatural so far has the following number of ratings…
Chrome x 8
Amazon x 23
iOS x 29
Android x 494
I’m going to find out how many times it has been downloaded/bought then try to work out the % of downloaders/buyers that actually leave ratings.