WASHINGTON — U.S. employers added a modest 199,000 jobs last month while the unemployment rate fell sharply, at a time when businesses are struggling to fill jobs, with many Americans remaining reluctant to return to the workforce.

The Labor Department also said Friday that the nation's unemployment rate fell to a healthy 3.9% from 4.2% in November. Though unemployment continues to fall, the U.S. in December added jobs at a slower rate than it did in November, when the economy added 210,000 jobs.

Speaking at the White House Friday, President Joe Biden said the report marked a "historic day," noting that the unemployment rate fell below 4%. He noted that it marked the sharpest single-year decline in unemployment in U.S. history.

However, the report fell short of analyst projections. CNBC reports that forecasters expected the U.S. had added 422,000 jobs in the month of December.

Though the highly-contagious omicron variant of COVID-19 began spreading the U.S. in December, CNBC spoke to forecasters that said the new strain likely did not have an impact on Friday's report. However, omicron will likely play a major role in January's job report, which will be released early next month.

Friday's report comes just days after a separate report found that more Americans than ever quit their jobs in the month of November. Biden said during his remarks Friday that more Americans are simply transitioning to new opportunities.

"Americans are moving up to better jobs with better pay, with better benefits," Biden said.

The Dow Jones Industrial Average is on the rise Friday following the release of the December jobs report.