Fewer low-income Americans took out mortgage loans last year than 2020, real estate broker Redfin said in a report Monday, as steep interest rates make homebuying less affordable.

As aggressive rate hikes by the U.S. Federal Reserve have pushed up the cost of standard 30-year mortgages to more than 7%, existing homeowners have held on to rock-bottom rates from the pandemic. That has limited the supply of homes for sale and resulted in higher prices.

Roughly 20.6% of new mortgages issued last year went to low-income Americans, down from 23.2% in 2020, bringing that group's piece of the homebuying pie back to where it was in 2018, according to the report, which analyzes Home Mortgage Disclosure Act (HMDA) data covering purchases of primary homes.

"Somewhat ironically, the continued strength of the economy has made it harder to afford a home and widened the real-estate wealth gap between rich and poor Americans," Redfin Senior Economist Elijah de la Campa said.

The median household income in the HMDA data for low-income households was $64,000.