Declining U.S. birth rates and a tighter grip on immigration means fewer workers in a booming economy with an unemployment rate of 3.5%, a 50-year-low, reports The Wall Street Journal.

The fertility rate for American women has continuously declined since the Great Recession ended in 2007 and reached an all-time low of 1.7 children per woman in 2018. The work force will surely diminish in the coming years as well, with many workers set to retire soon and young adults opting to stay in school longer, according to the Journal.

The long-run health of the economy is also in danger from the Trump administration's big cuts in immigration, although the immigrant population stopped growing before Trump took office.

Immigration to the United States fell 70% last year to only 200,000 people, the lowest level in more than a decade.

The result: a decline in the U.S.'s two longstanding demographic advantages over Germany and Japan: immigration and higher fertility.

Mark Mather, a demographer at the Population Reference Bureau, says the drop in birth rates likely will not change.

"We don't expect to see a bounce back any time soon," he told he Journal.

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