RIO DE JANEIRO (AP) — Latin Americans born into Roman Catholic families have increasingly left the faith for Protestant churches, while many others have dropped organized religion altogether in a major shift in the region's religious identity, according to a survey released Thursday.

While 84 percent of Latin American adults report they were raised Catholic, only 69 percent currently identify as such, said the Pew Research Center in Washington. At the same time, Protestants have gained members. About one in 10 Latin Americans were raised Protestant, but nearly one in five now call themselves Protestant. About 4 percent of Latin Americans report they were raised with no religion, but 8 percent say they have no tie to any faith.

The survey, conducted between October 2013 and February 2014, outlines the challenge for Catholic leaders in a region that was once a stronghold for the faith. Latin America still has about 425 million Catholics, or 40 percent of adherents worldwide, according to the poll. But the exodus from the church continues.

The losses were part of the reason for the 2013 election of Pope Francis, the former archbishop of Buenos Aires, Argentina, who is the first Latin American pontiff. In most countries of the region, two-thirds or more respondents held positive views of Francis. But the authors of the Pew report said former Catholics are more skeptical of the pope than those still in the church, with only a majority of ex-Catholics in Argentina and Uruguay viewing him favorably.

According to Pew, the percentage of Catholic-born people flocking to Protestant churches has steadily grown in recent decades in nearly all 18 countries and Puerto Rico where the poll was conducted. "In most of the countries surveyed, at least a third of current Protestants were raised in the Catholic Church, and half or more say they were baptized as Catholics," the authors of the report said.

Former Catholics who have embraced Protestantism most frequently cited a desire for a personal connection with God for leaving their original faith. Others said they wanted a different style of worship or a church that helps its members more.

The most Catholic countries were Mexico, with 81 percent Catholics and 9 percent Protestants, and Paraguay, with 89 percent Catholics and 7 percent Protestants.

Uruguay emerged as Latin America's most secular country, with 37 percent of people saying they were atheist or agnostic or had no religious affiliation. Just 42 percent of people from Uruguay say they're Catholic.

The more than 30,000 face-to-face interviews were conducted in all of Latin America's Spanish-speaking countries except Cuba. The margin of error varies by country, ranging from plus or minus three percentage points to four points.