Only 7% of Utahans are evangelical. It also has a relatively high percentage of non-religious, though I'm guessing most of these are probably ex-Mormons and their descendants.
Also, FWIW Obama got around 19% of the Mormon vote in 2008, though that was probably near the high-water mark for a Democrat in UT, and a feat he's obviously not going to replicate this year. Mormons made up 75% of the electorate in Utah, depsite making up only 60% of the state's population. Working backwards using algebra, that means Obama had to have gotten around 79% of the non-Mormon vote to get him to 34% of the vote.
Of course all this begs another question: why do Mormons have such high turnout?
Good question. Perhaps it's because they're part of a religion that's one of the most politically involved. I know they did a lot to help pass prop 8 in California, with many Mormons from other states canvassing in California for the cause. I think the Mormons have been very successful in shaping Utah's politics and they have had influence in other states as well, so they understand the value of being politically active.
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