The study however is not a general way to represent a global specimen, but based on user of smartphones in America only. In terms of percentage, 9% of iPhone users use mobile networks, while 68% of the ANdroid users are on ot. Comparatively, 71% of the iPhone users use WiFi and only 32% of the Android users are into it. This only shows where the trend for the advertisers must head to.
However in UK, WiFi is big with Android users, but at the same time, it is huge with iPhone users too, who also use mobile network equally. It then goes down to habit of browsing the internet basically or it could be about the strength of the WiFi connection and mobile networks services in these two regions while creates the difference.
Here below is the result of iPhoen and Android users WiFi usage survey in US and UK: