I don't have exact numbers, but I wouldn't be surprised if 80-90% of google ad revenue comes from the ad prices they can charge for US users. I would be shocked if the percentage was less than 50-60% of revenue from US alone, which would put the value extraction per user for google at ~10$/month/user
Sorry, I mean that the revenue seems to not just be search ad revenue but ad revenue. Google's ad revenue comes from a lot of places, such as in your Android app. I assume it also includes adsense and other things.
