I don’t know how this data was acquired other than saying it was a self-reported study, but since it got Jordan Lorence of the Alliance Defense Fund all worked up, it must be worth talking about.
It turns out that, on the whole, atheists and agnostics make up the largest percentage of current Yale Law School students, narrowly edging out all the Christians (Thanks, 2Ls!):


Atheists and Agnostics make up 33.8% of YLS, while Christians make up 33.2%.
Anyone know if this breakdown is similar at other top law schools?