<p>I've generated graphs that more directly answer your question <a href="https://stats.meta.stackexchange.com/a/2086/1036">here</a>.</p>

<p><img src="https://i.stack.imgur.com/8ek3H.png" alt=""></p>

<p>That was over two years ago, but you <a href="http://data.stackexchange.com/stats/query/203684/the-long-tail-of-answers" rel="nofollow noreferrer">could update with newer data if you want</a>. Two years ago we were in the middle of the pack. The Math and Mathematica site were more dominated by a smaller number of users, and theoretical computer science is the most even.</p>

<p>Also see this question about generating <a href="https://stats.meta.stackexchange.com/a/2986/1036">Gini scores for sites</a>. For that metric the cut-off you use to count users matters a lot. </p>
