It is not that good. My site recieves about 3-4% and I think that is low. However there are a lot of ways to increase your earnings. Some of them include positioning your ads bette, coloring them to fit your website, deleting frames around the ads, monitoring the lrelevacy of your ads and so on. I have written an article on how to make money with adsene if you want to read it. Good luck! =)