If you skip back to the OP you'll see the issue isn't about the percentage of white evangelicals who appreciate Trump (75% approve of the job he's doing) but the percentage who currently approve,
AND say almost nothing Trump could could do would lose their approval.(37%)
Now. . .
The Pew Research Center 2014 survey in the United States identified the evangelical percentage of the population at 25.4 percent while Roman Catholics are 20.8 percent and mainline Protestants make up 14.7 percent.
source:America’s Changing Religious Landscape Pew Research Center May 12, 2015.
Taking the percentage figures (25% and the 37%) for evangelicals in the USA as relatively accurate, this means that about 9.25% of adult Americans, (23,473,548 of them) feel almost nothing Trump could could do would lose their approval.
24.5 million people! Now
that's scary
.
.