I tried to look at the source site, but they want you to pay them, and give them your email to sign up for their newsletter.

Is there an actually reliable way to check their source? How did they get this information? And does this include accounts set to Private?

Its not incredibly surprising given China has the second most Steam accounts and the most active Steam accounts in the world already. But I would like to actually see the source on this data and I am curious about other games as well.