A bit on differences between 2016 and 2015
A year ago I wrote that an average game on Steam had 32,000 owners. I've just checked, and this number dropped to 21,000.

Obviously, I got interested and did some digging. Here are the results.

As you'd probably expect, we saw a lot of new games released since the last year, and they've skewed the numbers toward lower sales. But the distribution of sales (second graph) remains pretty much the same with some minor increase in lower sales and minor decrease in the middle.

Or, in layman terms: we've got a lot of new bad-selling games on Steam, but it didn't affect the top games, which still sell pretty well.