MIAMI — Having fled economic and political chaos in Venezuela, Luisana Silva now loads carpets for a South Carolina rug company. She earns enough to pay rent, buy groceries, gas up her car — and send money home to her parents.

Reaching the United States was a harrowing ordeal. Silva, 25, her husband and their then-7-year-old daughter braved the treacherous jungles of Panama’s Darien Gap, traveled the length of Mexico, crossed the Rio Grande and then turned themselves in to the U.S. Border Patrol in Brownsville, Texas. Seeking asylum, they received a work permit last year and found jobs in Rock Hill, South Carolina.

“My plan is to help my family that much need the money and to grow economically here,” Silva said.

Her story amounts to far more than one family’s arduous quest for a better life. The millions of jobs that Silva and other new immigrant arrivals have been filling in the United States appear to solve a riddle that has confounded economists for at least a year:

How has the economy managed to prosper, adding hundreds of thousands of jobs, month after month, at a time when the Federal Reserve has aggressively raised interest rates to fight inflation — normally a recipe for a recession?

Increasingly, the answer appears to be immigrants — whether living in the United States legally or not. The influx of foreign-born adults vastly raised the supply of available workers after a U.S. labor shortage had left many companies unable to fill jobs.

More workers filling more jobs and spending more money has helped drive economic growth and create still-more job openings. The availability of immigrant workers eased the pressure on companies to sharply raise wages and to then pass on their higher labor costs to their customers via higher prices that feed inflation. Though U.S. inflation remains elevated, it has plummeted from its levels of two years ago.

“There’s been something of a mystery — how are we continuing to get such extraordinary strong job growth with inflation still continuing to come down?” said Heidi Shierholz, president of the Economic Policy Institute and a former chief economist at the Labor Department. “The immigration numbers being higher than what we had thought — that really does pretty much solve that puzzle.”

While helping fuel economic growth, immigrants also lie at the heart of an incendiary election-year debate over the control of the nation’s Southern border. In his bid to return to the White House, Donald Trump has attacked migrants in often-degrading terms, characterizing them as dangerous criminals who are “poisoning the blood” of America and frequently invoking falsehoods about migration. Trump has vowed to finish building a border wall and to launch the “largest domestic deportation operation in American history.” Whether he or President Joe Biden wins the election could determine whether the influx of immigrants, and their key role in propelling the economy, will endure.

The boom in immigration caught almost everyone by surprise. In 2019, the Congressional Budget Office had estimated that net immigration — arrivals minus departures — would equal about 1 million in 2023. The actual number, the CBO said in a January update, was more than triple that estimate: 3.3 million.

Thousands of employers desperately needed the new arrivals. The economy — and consumer spending — had roared back from the pandemic recession. Companies were struggling to hire enough workers to keep up with customer orders.

The problem was compounded by demographic changes: The number of native-born Americans in their prime working years — ages 25 to 54 — was dropping because so many of them had aged out of that category and were nearing or entering retirement. This group’s numbers have shrunk by 770,000 since February 2020, just before COVID-19 slammed the economy.

Filling the gap has been a wave of immigrants. Over the past four years, the number of prime-age workers who either have a job or are looking for one has surged by 2.8 million. And nearly all those new labor force entrants — 2.7 million, or 96% of them — were born outside the United States. Immigrants last year accounted for a record 18.6% of the labor force, according to the Economic Policy Institute’s analysis of government data.