How Many Evangelicals Voted for Trump?

From the Christian Post:
Much of the media is reporting that 81 percent of evangelicals voted for Trump, using exit polling data. Notable conservative evangelicals are challenging this statistic, contending the figure is somewhere between 35 and 45 percent, and many of them did so begrudgingly.
There are three problems with the “81 percent” figure, they say: 1) the number only includes white evangelicals, 2) the number doesn’t account for participation, so one who self-identifies as an evangelical but never goes to church would be included, and 3) the number is only a portion of those who voted and doesn’t account for the evangelicals