PHOENIX — Arizona needs its 920,000 foreign-born residents, both legal and otherwise, to fuel the state’s economy, according to a new study and some business leaders.

The report Monday by the New American Economy says those families had $21.4 billion in household income in 2014, the most recent figures available. They paid $1.7 billion in state and local taxes and have $16 billion in spending power.

When just the undocumented are counted, their earnings were $3.5 billion and $3.1 billion in spending power.

And the number of foreign-born immigrants living in Arizona grew faster between 2010 and 2014 than the overall rate of growth, both from births and people moving here from other states.

Kate Brick, the organization’s director of state and local initiatives, said all that means more money in the economy, more dollars into Social Security and Medicare, and more people buying homes which in turn keeps the value of housing here increasing.

But the report, done for the Arizona Chamber of Commerce and Industry, also shows that migrants represent a disproportional share of people in lower-wage jobs, including 32 percent of janitors and building cleaners, 50 percent of grounds maintenance workers and 55 percent of people working as maids or in housekeeping.

And Randy Johnson, a vice president of the U.S. Chamber of Commerce, said up to 60 percent of the agriculture workforce is not just foreign born but also undocumented.

More to the point, he said the industry is dependent on that. And Johnson said any federal legislation to require employers to electronically check the legal immigration status of their workers is dependent on farmers and others being able to get the laborers they need in some way.

“Let’s just say it: They can’t work without undocumented workers in the workforce,” he said.

Glenn Hamer, president of the state chamber, insisted it’s not simply a matter of farmers paying higher wages to attract people who are here legally.

First is the question of whether legal residents would take those jobs. That’s not a new argument.

“I don’t think I need to tell you that there are jobs that Americans will not do,” U.S. Sen. John McCain famously said in 2008. And when audience members suggested the issue is paying higher wages, the senator offered $50 an hour to anyone who would pick lettuce in Yuma for the whole season.

“You can’t do it, my friend,” he said.

Hamer said it’s irrelevant whether people will take certain jobs even if the wages are increased.

“Those farms couldn’t exist,” he said. “They would go elsewhere.”

Hamer said that’s already happened with some operations moving to Mexico.

“Who wins there?” he said. “The entire ecosystem gets blown to smithereens.”

Johnson also denied that all the national chamber wants is cheap labor.

“If we wanted just cheap labor, you’re right, we wouldn’t support legalization,” he said, allowing those who are undocumented and already here to remain subject to some conditions, like a background check.

Anyway, he said, it’s better than “this sort of wink and a nod that we create through an I-9 system.” That refers to the current requirement that employers verify the legal status of workers by logging in documents they present, a system that is generally considered to be rife with loopholes and people using forged and stolen papers.

But there’s something standing in the way of interest of the business community in legalizing all the undocumented workers they are now using.

State Rep. Noel Campbell, R-Prescott, said he doesn’t have a problem with providing legal status to the estimated 11.3 million — perhaps 325,000 in Arizona — who are undocumented. But he said that there’s a political reality to get the votes.

“We have to have the border secured first,” said Campbell who worked for 27 years for U.S. Customs and Border Protection, reflecting the views of many within his party.

“We’re never going to secure it 100 percent,” he said, citing his time on the border.

“But once we can accomplish that, then other steps can happen.”

Brick acknowledged the concentration of foreign-born workers in some jobs, but said the data shows they are not all concentrated in lower-wage jobs.

She said they make up 17.3 percent in STEM jobs — science, technology, engineering and math — despite being just 13.7 percent of the state population. And Brick said if half of the state’s 1,070 foreign students on temporary visas who earned advanced STEM degrees stayed in Arizona, they would create more than 1,400 jobs for U.S.-born workers by 2021.

And there’s something else: 71 percent of foreign-born workers are of working age, compared with 47 percent of those born in this country. She said that helps fuel the economy.

Victoria DeFrancesco Soto, an adjunct professor of public affairs at the University of Texas, had a slightly different take on the issue.

She said Hispanic women have a birth rate of 2.4 children, versus 1.8 for others. And all those children, Soto said, will help contribute to keeping Social Security solvent for what is becoming an aging population.

On Twitter: @azcapmedia