Yes. But the term "evangelicals as a whole" isn't clearly defined. They've adopted a specific definition, based on answers to some questions. I assume they are the questions to which 100% of evangelicals agreed:
- The Bible is the highest authority for what I believe.
- It is very important for me personally to encourage non-Christians to trust Jesus Christ as their Savior.
- Jesus Christ’s death on the cross is the only sacrifice that could remove the penalty of my sin.
- Only those who trust in Jesus Christ alone as their Savior receive God’s free gift of eternal salvation.
You'd get a different result if you asked people whether they consider themselves evangelical, or if you used different questions.
This will have the same problem that political survey have: how accurately does the sample represent US Christians? They've tried to get a good sample, but there could well be unintentional biases. If you've followed discussions about the presidential election, you'll know that Trump did better than the polls indicated. Why? One guess is that people conducting surveys didn't get a completely representative sample. The same thing could happen here, but remember that the political surveys were accurate to a few percent. It's just that in a close election that matters.
So I wouldn't take the percentages as precise. But I'd guess that the results are roughly right, given their definitions of evangelical and other categories.