Net international migration hit its lowest level of the decade between 2018 and 2019, according to a preliminary analysis by the U.S. Census Bureau.
Net migration added 595,000 to the U.S. population between 2018 and 2019, a marked decrease from the decade high of 1,047,000 between 2015 and 2016.
The figure measures the difference between people moving to a country from the number of people leaving a nation.
States most likely to be affected by the trend are Florida, California, Texas, New York and Massachusetts, which usually attract the most migrants from abroad, according to the Census Bureau.
Growth in net international migration has been declining since 2016. In addition, more immigrants are coming from China and India, while immigration from Mexico has "dropped significantly" following the Great Recession, according to the Census Bureau.
"In 2018, births hit a three-decade low. Our population is rapidly aging," Buttigieg's team wrote in an immigration white paper. "Absent increases in immigration, GDP growth will decrease by 1.4 percent a year over the next decade. And it's not only a rising population that increases GDP; diversity itself is a driver of economic growth."