Those Americans who identify as white Christians are now considered to be a minority of the country’s population, according to a new survey.

The number has dipped below 50 percent, a transformation fueled by immigration and by growing numbers of people who reject organized religion altogether, said a report released Wednesday by the Public Religion Research Institute (PRRI).

While Christians overall remain a large majority in the U.S., at nearly 70 percent, white Christians – once a mainstay of the country's religious life -- now comprise only 43 percent of the population.

The change is likely due to several factors, including sharp drops in membership in predominantly white mainline Protestant denominations such as Presbyterians and Lutherans; an increasing Latino presence in the Roman Catholic Church as some non-Hispanic white Catholics leave, and shrinking ranks of white evangelicals.

About 17 percent of Americans now identify as white evangelical, compared to 23 percent a decade ago, according to the survey. Membership in the conservative Southern Baptist Convention, the largest U.S. Protestant group, dropped to 15.2 million last year, its lowest number since 1990, according to an analysis by Chuck Kelley, president of the New Orleans Baptist Theological Seminary.

"So often, white evangelicals have been pointing in judgment to white mainline groups, saying when you have liberal theology you decline," said Robert Jones, chief executive of PRRI. "I think this data really does challenge that interpretation of linking theological conservatism and growth."

The survey of more than 100,000 people was conducted from January 2016 to January of this year and found that the Protestant majority that shaped the nation's history had dropped below 50 percent sometime around 2008.

The poll also includes a more in-depth focus on race and religion. Jones said growth among Latino Christians, and stability in the numbers of African-American Christians had partly obscured the decline among white Christians.

The survey also found that more than a third of all Republicans say they are white evangelicals, and nearly three-quarters identify as white Christians. By comparison, in the Democratic Party, white Christians have become a minority shrinking from 50 percent a decade ago, to 29 percent currently.

The trends identified in the survey are fueling anxiety about the place of Christians in society, especially among evangelicals who are alarmed by support for same-sex marriage and by the increasing share of Americans — about one-quarter — who don't identify with a faith group.

President Donald Trump, who repeatedly promised to protect the religious liberty of Christians, drew 80 percent of votes by white evangelicals, a constituency that remains among his strongest supporters.

The Associated Press contributed reporting to this article.