Odds are that you know Mother Teresa was Catholic, but what religion is the Dalai Lama?

How about Maimonides?

And - no Googling - what's the first book of the Bible? How about the first four books of the New Testament?

Americans who can answer all of those questions are relatively rare, a huge new study has found.

In fact, although the United States is one of the most religious developed countries in the world, most Americans scored 50 percent or less on a quiz measuring knowledge of the Bible, world religions and what the Constitution says about religion in public life.

The survey is full of surprising findings.

For example, it's not evangelicals or Catholics who did best - it's atheists and agnostics.

It's not Bible-belt Southerners who scored highest - they came at the bottom.

Those who believe the Bible is the literal word of God did slightly worse than average, while those who say it is not the word of God scored slightly better.

Barely half of all Catholics know that when they take communion, the bread and wine literally become the body and blood of Christ, according to Catholic doctrine.

And only about one in three know that a public school teacher is allowed to teach a comparative religion class - although nine out of 10 know that teacher isn't allowed by the Supreme Court to lead a class in prayer.

The Pew Forum on Religion & Public Life is behind the 32-question quiz, polling more than 3,400 Americans by telephone to gauge the depth of the country's religious knowledge.

Read CNN Belief Blog contributor and Pew adviser Stephen Prothero's take on the survey

"When it comes to religion, there are a lot of things that Americans are unfamiliar with. That's the main takeaway," says Greg Smith, a senior researcher at the think tank and one of the main authors of the survey.

Smith has a theory about why atheists did so well on the quiz - they have thought more about religion than most people.

"Very few people say that they were raised as atheists and agnostics," he explains.

About three out of four were raised as Christians, he says.

"They were raised in a faith and have made a decision to identify themselves with groups that tend to be fairly unpopular," atheists and agnostics, he says.

"That decision presupposes having given some thought to these things," which is strongly linked with religious knowledge, he says.

The single strongest factor predicting how well a person does on the religious knowledge quiz is education - the more years of schooling a person has, the more they are likely to know about religion, regardless of how religious they consider themselves to be, Pew found.

"The No. 1 predictor without question is simply educational attainment," Smith said.

The think tank also asked a handful of general knowledge questions - such as who wrote "Moby-Dick" and who's the vice president of the United States - and found a link between religious knowledge and general knowledge.

Very few people scored high on religion questions and badly on general knowledge, or vice versa.

People who were members of religious youth groups also did well, he said.

"Religious education is an important factor that helps to explain knowledge - people who participated in youth groups get an average of two extra questions right," he said.

Jews and Mormons were close behind atheists and agnostics as the group who did best overall on the religion questions, and white evangelical Protestants also tended to get more than half right.

White Catholics averaged exactly half right, followed by mainline Protestants and people who said they were "nothing in particular," both of whom got just under half right.

Black Protestants got just over a third of the questions right, and Hispanic Catholics just under a third, the Pew Forum found.

The survey was inspired partly by CNN Belief Blog contributor Stephen Prothero's 2007 book, "Religious Literacy: What Every American Needs to Know - And Doesn't."

Because the Pew Forum couldn't find any indication that such a survey has ever been done before, it can't say if Americans today know more or less about religion now than they did in the past.

And the organization doesn't claim too much for its 32 questions.

They "are intended to be representative of a body of important knowledge about religion; they are not meant to be a list of the most essential facts," the Pew Forum says.

Only eight of the 3,412 survey respondents got all 32 questions right. Six got them all wrong.