In the 50 years since Congress broadly reconfigured immigration to open the country to newcomers from around the world, 59 million foreign-born people have come to the United States, more than quadrupling the number of immigrants who were in the country in 1965 and bringing their share of the population close to the peak of another great influx a century ago, according to a report published Monday by the Pew Research Center.

Since the Immigration and Nationality Act was passed in 1965, immigration has been the major driver of the country’s growth, with new immigrants, their children and grandchildren accounting for 55 percent of the increase, the report found.

A shift in priorities in the law brought major changes in flows of immigrants and the makeup of the nation, Pew researchers found. Whereas in 1965 most immigrants came from Europe, since then about half of all immigrants have come from Latin America, with one country, Mexico, sending by far the most people. About 16 million immigrants came from Mexico in the last five decades, or about 28 percent of all newcomers.

Arrivals from Europe, the main source of immigrants for most of the nation’s history, now make up 10 percent of new foreign-born residents.

But according to the report, since 2011 there has been another significant shift, with people from Asia — mainly India and China — now surpassing the numbers from Latin America. The change is striking because Chinese and most other Asian immigrants were barred from coming to live in the United States for many years in the late 19th and early 20th centuries.

The Pew Research Center published the report to coincide with the 50th anniversary this week of the immigration act, which put an end to a system that was based on country quotas that overwhelmingly favored immigrants from Northern Europe. The new system opened legal immigration to people from all countries, putting the top priority on bringing in family members of people living in the United States, especially American citizens, while also seeking to draw foreigners with desirable work skills.

“This most recent period really does reflect the notion that the United States is a nation built on immigration and has been able to absorb many immigrants from different parts of the world,” said Mark Hugo Lopez, the director of Hispanic research at the Pew Center. He is an author of the 103-page report, along with Jeffrey Passel, the center’s senior demographer, and Molly Rohal.

Today, in raw numbers, 45 million immigrants live in the country, up from just under 10 million in 1965, by far the largest foreign-born population in United States history. (About 14 million of the foreigners who came since 1965 have died or left.) The foreign-born share is now 14 percent, approaching the high point of 15 percent during the great European immigration in the early 20th century.

Numerical limits on legal visas that Congress imposed in 1965 and in subsequent years ushered in a period of surging illegal immigration. The report’s tally of the current foreign-born population includes 11.3 million immigrants here illegally.

The Pew report casts light on the uneasiness some Americans have expressed about the shifts in society in the United States. In 1965, the researchers found, whites made up 84 percent of people in the country. By this year, their share had declined sharply, to 62 percent.

“Historically this is perhaps the lowest we have seen the non-Hispanic white share in U.S. history,” Mr. Lopez said.

According to Pew projections based on current trends, by 2055 whites will lose their majority status in the population, and their share will continue to decline. Pew projects that after 2055, no ethnic or racial group will be a majority of the population.

As the share of whites has decreased, Latinos have been the fastest-growing group over the last five decades, and today they are 18 percent of the population, up from 4 percent in 1965. Almost half — 47 percent — of all immigrants are from Latin America, and by 2065 one in four people in the United States will be Latino.

At the same time, in recent years immigration from Latin America has been slowing, mainly because of what the report calls an “abrupt slowdown” of illegal immigration from Mexico. With Mexicans accounting for only 15 percent of all new immigrants in 2013, the Pew report found, the share of newcomers who are Latino is at its lowest level in five decades.

In a poll included in the report, Americans are divided about whether immigration has helped or hurt the country. About 45 percent of adults in the survey said immigrants were “making American society better in the long run,” while 37 percent said they were making it worse. Among whites, opinion was split, with 41 percent saying immigrants help American society and 43 percent saying they make it worse.

Republicans have a starkly negative view of immigration, with 53 percent of adults who identified as Republican saying immigrants make the country worse and only 31 percent saying they make it better. The sentiments are reversed for Democrats, with about 55 percent saying immigrants make the country better and only 24 percent saying they make it worse.

In 2013, the report found, arrivals from Asia made up 41 percent of new immigrants, their highest level in American history. Asians are now 6 percent of the population, with immigration accounting for virtually all of their recent growth. Most Asians are legal immigrants with high levels of education who have come to the United States with visas based on their employment skills rather than their family ties.

In part as a result of the Asians’ arrival, education levels of immigrants over all are rising. Among new immigrants in 2013, 41 percent had at least a bachelor’s degree. About 30 percent of native-born Americans have completed a college degree.

Over the next 50 years, the Pew report predicted, immigrants and their descendants will play an even greater role in the country’s growth. If current trends continue, it says, they will account for almost 90 percent of growth, bringing the total population to 441 million.

The opinion results were from a survey in Spanish and English of 3,147 adults conducted online from March 10 to April 6 by the Pew Research Center, with a margin of sampling error of plus or minus two percentage points.

http://www.nytimes.com/2015/09/28/us/share-of-immigrants-in-us-nears-highs-of-early-20th-century-report-finds.html