The population of the United States is becoming less white, as more non-white people enter the population while the number of whites continues to decrease due to a low birth rate. Asians are now the fastest growing demographic group in the U.S.

The U.S. Census Bureau revealed for the first time that nonwhites and Hispanics now comprise a majority of people under the age of 16. It said this remarkable demographic shift in 2019 will grow over the coming decades.

Also, the number of non-Hispanic whites has grown smaller over the past decade as deaths surpassed births in this aging demographic, according to population estimates by the U.S. Census Bureau.

Census data shows almost 40% of the total U.S. population was either nonwhite or Hispanic in 2019. Non-Hispanic whites, or those people we now refer to as white Americans, are expected to be a minority of the U.S. population in 25 years.

The dramatic decline in the number of non-Hispanic whites stems from a natural decrease in their numbers due to there being more deaths than births. Another factor limiting their numbers is a slowdown in immigration to the U.S. exacerbated by president Donald Trump's anti-immigration policies.

These twin factors and others contributed to the population drop since 2010 for non-Hispanic whites. Non-Hispanic whites are also older than the general population. Their median age of 43.7 years-old in 2019 is the highest of any demographic group by far.  

Census population estimates shows the reduction in the number of whites that aren't Hispanic has escalated over the past three years. The number of non-Hispanic whites plummeted by more than 500,000 people from 2016 to 2019.

"We are browning from bottom up in our age structure," said William Frey, a senior fellow at The Brookings Institution. "This is going to be a diversified century for the United States, and it's beginning with this youngest generation."

If these numbers remain true in the 2020 census now being conducted, it will be the first time since the first decennial census in 1790 there has been a national decline of the number of non-Hispanic whites, according to Frey.

He said it's due to aging. He noted immigration hasn't decreased that much but white fertility has dropped.

Asians had the biggest growth rate of any demographic group, increasing by almost 30% over the past decade. Census data shows almost two-thirds of this growth was due to international migration.

The Hispanic population has increased by 20% since 2010. Some three-quarters of this increase came from a natural increase, meaning more people are born than die. The Black population increased by some 12% over the past decade. On the other hand, the white population posted a smaller increase at 4.3%.