The findings of a Pew Research Centre Report released on Monday provide a 100-year look at immigration’s impact on American population growth and on racial and ethnic change, showing that immigration will shape and change the future population of America.  Without immigration the population would begin to decline over the next 50 years, with immigrants and their descendants projected to account for 88 percent of population growth by 2065, as shown in the following chart:  Many demographers consider the United States fortunate to have its work force propped up thus, as the population ages and fertility rates fall.  Pew Research demographer Jeff Passel comments that: "Without the immigrants, the U.S. population would start decreasing... The big picture is that immigration has been the major demographic factor driving growth and change in the U.S. population over the last 50 years."
Between 1965 and 2015, new immigrants, their children and their grandchildren accounted for 55% of U.S. population growth.  The 1965 Immigration and Nationality Act made significant changes to U.S. immigration policy by no longer favouring immigrants from Europe, but rather family reunification and skilled immigrants. As a result Asia is now the largest source region among recently arrived immigrants and has been since 2011.
Over the next 50 years the United States will become a country where no one racial or ethnic group is a majority.  Non-Hispanic whites are projected to become less than half of the U.S. population (46%), Hispanics will rise to 24% from 18% today, and Asians to 14% from 6% today. 
The public perception of immigration is mixed.  According to the study, 47% of American adults say immigrants from Asia have had a mostly positive impact on American society, and 44% say the same about immigrants from Europe. Half say the impact of immigrants from Africa has been neither positive nor negative. However, Americans are more likely to hold negative views about the impact of immigrants from Latin America and the Middle East. From an economic perspective, The Financial Times comments of the findings that:

A growing US population, fuelled by arrivals of well-qualified foreigners, should be supportive of economic growth, at a time when many advanced countries face more ageing populations. The profile of those arriving shows they are well educated — and more likely than US-born adults to have a university degree.

Bill Frey, a demographer at the Brookings Institution, said: “This pushback about undocumented immigration which tends to dominate political debates put to the backburner a more rational discussion about immigration policy. We are going to have to have a reasonable flow of immigration to the US to keep our labour force robust.”  
It is an interesting look at how low fertility rates are changing the shape of many societies.