The link in that article has some interesting things:
I'm surprised it's that close to the national average.
It's that high here? I know the Midwest is very far from a hotbed of secularism but I'm surprised we compare to the South.
In response to the third point, let me paraphrase: "Unchurched people are far less likely to lie when this question is asked."
That's notably high and interestingly close to the number who define themselves as Christian when you consider the atheists in the group who would disagree with this statement (as they believe no one goes to Heaven.)
Doesn't really jive with the Christian identifying numbers.