The U.S. faces a shortage of 7.4 million affordable rental units for poor families, according to a report released Thursday that illuminates the extent of the rental housing crisis that awaits Ben Carson as he plans to take over as President Trump's secretary of Housing and Urban Development this week.

For every 100 extremely low-income families, an average of just 35 affordable rental units are available throughout the country, according to the National Low Income Housing Council.

The shortage of available apartments is prevalent across the country, according to the report. New York City alone is short nearly 640,000 affordable units.

"This year's analysis continues to show that the poorest households in our nation face the largest shortage of affordable and available rental housing and have more severe housing cost burdens than any other group," said Andrew Aurand, the vice president for research at the council.

The group's analysis, which is based on data from the American Community Survey conducted by the Census Bureau, defines an extremely low-income family as one below the poverty line or making less than 30 percent of median income in an area. Housing affordability means that the family is paying no more than 30 percent of its income on rent.

Past secretaries of the Department of Housing and Urban Development have said that the country faces a rental "crisis" because more than one-third of renters are spending more than the recommended amount on housing, and about one in eight are spending more than half their income on rent.

Trump's nominee for HUD secretary, famed pediatric neurosurgeon and former presidential candidate Ben Carson, was set to receive a final vote on his confirmation Thursday morning.

While the agency spends about $50 billion annually on providing support for low-income housing, according to a 2015 Congressional Budget Office report, only about a quarter of eligible families receive assistance. Others are on waiting lists for assistance or don't have access.

During confirmation hearings, Carson did not give specifics about his plan for providing affordable housing but said that he would embark on a national listening tour to devise a strategy for addressing the problem.

The National Low Income Housing Council advocates spending more federal money on housing assistance. This week, it recommended freeing up funds to do that by reforming the mortgage interest tax deduction, a benefit that currently disproportionately aids higher earners.