How to obtain research data about IT related subjects? I'm doing a study which requires me to get data about which operating systems are used the most on mobile devices. Since I need to refer to the sources in the official document, those sources need to be confirmed. I've seen some researches, but I either can't confirm the source, or need to pay to see the survey/research.

Is there a way to obtain data on this subject? Or, preferably, on all IT-related matters?
Statista.com claims to be what you're looking for: a statistics aggregator. However, I don't think there's a general well-defined methods to get any statistics.

The way I usually proceed is that I attempt to find as many statistics as possible from multiple sources, I eliminate the ones that are too old / really inconsistent with the others / describe a shaky methodology for data collection, and I present all the remaining statistics. So instead of having one reference for a peer-reviewed document, I get 3 or 4 concurring non-peer-reviewed documents.

EDIT: one other important aspect is how 'fresh' the data you use is. First-hand accounts from Microsoft about Windows apps are arguably trustworthy. Second-hand accounts that don't indulge too much in interpretation and who publish rigorous documents (the difference between Financial Times and BuzzFeed) can be used, too, ideally having multiple sources. For any other source or things that are more than second-hand, you want a large consensus over multiple sources.