Interesting, but as usual it depends what questions the pollsters ask. A report in my local newspaper last Saturday, which interested me enough to clip out and save, said 44% of Americans told the Baylor University Religion Survey in 2011 that they spend no time seeking "eternal wisdom, " and 19% said "it's useless to search for meaning." 46% in 2011 told an evangelical research agency based in Nashville called Lifeway Research that they never wonder whether they'll go to heaven (though that might just mean they're sure they will), 28% said "It's not a major priority in my life to find my deeper purpose," and 18% reportedly scoffed at the idea that god has a plan or purpose for everyone.Your right, American's for the most part believe in God 90+% ...
More nuanced questions suggest the U.S. might be a good deal more secular than is commonly believed, and maybe the secularists just don't stand for public office or go to political rallies. True believers are still a clear majority, so much so that you'd have no chance of being elected in most jurisdictions if you stood up and announced disbelief, and in some places it'd be actively dangerous to do so. It remains true that the level of religious observance is the U.S. is anomalously high compared to other western democracies, you have to go into the Third World to find anything that matches it, but a simplistic question like "Do you believe in god?" won't distinguish a deist from a theist from a flaming fundamentalist.