America has always been a forerunner in freedom. One freedom that large numbers of Americans are using is religious freedom.

Nearly 30 percent of Americans have changed religious affiliation from what they were raised in, according to the U.S. Religious Landscape Survey conducted by the Pew Forum on Religion and Public Life. This includes all major religions, Christian and Eastern traditions and includes those who don't claim a religion. When including Protestant denomination changes and changes with citizens claiming no affiliation, the total jumps to 44 percent.

Darren Sherkat, a professor of sociology at Southern Illinois University has studied what is often termed religious mobility. He has published several papers on why people change faiths.

"Normal things are the biggest things in the decision to change religions," Sherkat said.

The "biggest things" include geography and family. If an individual or family moves, they are often forced to find a new church, Sherkat said.

Marriage is the second largest factor. Most Americans are going to marry someone of their own faith, Sherkat said. However, many don't. Either one partner will change or both will change.

"It is equally common that both spouses will move to a different denomination," Sherkat said.

One surprising fact is that the number of unaffiliated Americans, those who are atheist, agnostic, or claim no particular faith, has grown over the last decade. About 16 percent of Americans fit into this category. In the study, only a little over seven percent said they were raised that way.

"People are actively embracing a lifestyle that excluded religion," Sherkat said. "Many more are being born non-religious and staying that way. People are exiting religion."

While some may see this as disconcerting, Sherkat views it as liberating. Americans shouldn't have to have Christian views forced upon them through the pledge of allegiance or currency that states a belief in God.

"For those of us who are non-Christian that is an important thing," he said.

Nancy Ammerman, a professor of sociology at Boston University pointed out that the unaffiliated group consists of several smaller groups.

"The unaffiliated are not necessarily non-believers," she said. "The number of non-believers or atheists is also growing but is still small."

Ammerman, who has studied American congregations, said she sees every reason to believe that the unaffiliated group will continue to grow.

"However, American religion is so inventive," she said.

American history has shown how people are willing to adapt, alter, or start over altogether. That can be seen in the religious revivals of early America, Ammerman said.

"If we have a pool of unhappy people, someone will invent a new way to be religious," she said. "It worked for Joseph Smith."

Ammerman said religious change takes place around two things: family and education. She agrees with Sherkat that marriage has a profound influence on the faiths chosen.

"The role of education is more complicated," she said.

College is often stereotyped as a place that will destroy a person's religion, but Ammerman said that isn't true. College is where many are introduced to other religions.

"It's the melting pot," she said.

People moving between Christian denominations see no real change said Roger Keller, professor of Church History at BYU.

"To switch denominations is no big deal," Keller said. "Those kinds of things shouldn't surprise us."

People are looking more for a preacher or style of worship, he said. Some people do make drastic changes from Christianity to Buddhism, but these are rare. Most switches are to something similar, such as within Christian denominations.

Family appears to be a large factor in religious retention. The American Bible society recently completed a study that showed a correlation between parents' activity in religion and their children's activity. Roy Lloyd, spokesperson for the American Bible Society, said that parents have a large influence.

"Parents are, by far, the role models for teens," Llyod said in an email.

A common stereotype for teens is that they aren't interested in religion.

"On the contrary, we are finding a deep well of interest in faith questions and experiences," Lloyd said.

In his studies, Roger Fine, professor of sociology and religion at Penn State, has seen that family is the largest influence on whether individuals stay in a religion.

"Family would be key," he said. "Unless [children] are trained in why their religion is true they won't stay."

What is the future for American religion? America may continue to be the shifting marketplace of theology and faces it always has been. Religion, the search for answers to life, will continue to play a large role in Americans' lives and may not relax anytime soon.

"It's always changing and in a wide variety of ways," Finke said.