New data show homeownership is becoming increasingly unaffordable.

In its fourth-quarter 2020 U.S. Home Affordability Report, ATTOM Data Solutions says that median home prices of single-family homes and condos were less affordable than historical averages in 55% of counties. That was an increase over the 43% posted a year ago and 33% from three years ago.

Fifty-five percent of counties—275 of 499 analyzed—were less affordable than past averages. In Q4 2019, 217 counties were less affordable than past averages. In Q4 2017, 164 hit that mark.

Overall, homeownership expenses consumed 29.6% of the average wage across the nation during Q4 2020. In Q4, 2019, that figure was 26.4%. Those costs exceeded the benchmark in 59% of the counties included in the Q4 2020 report.

“Owning a home in the United States slipped into the unaffordable zone for average workers across the nation in the fourth quarter as the numbers continued a year-long slide in the wrong direction. The latest housing market data shows the average worker unable to meet the 28% affordability guideline used by lenders,” said Todd Teta, chief product officer with ATTOM Data Solutions in a statement.

Forty-one percent of counties, including Cook County (Chicago), Ill.; Harris County (Houston), Texas; Philadelphia County, Penn., Hillsborough County (Tampa), Fla. and Cuyahoga County (Cleveland), Ohio, had major homeownership expenses on typical homes in the fourth quarter that were affordable for average local wage earners.

Los Angeles County, Calif., Maricopa County (Phoenix), Az.; San Diego County, Calif.; Orange County, (outside Los Angeles), Calif., and Miami-Dade County, Fla. were the most populous of the 296 counties with unaffordable major expenses on median-priced homes for average earners in Q4 2020, according to ATTOM.

Overall, median home prices rose by at least 10% in 79% of the 499 counties included in Q4. The most significant year-over-year gains in median prices among counties with a population of at least 1 million occurred in Cook County (up 32%), Philadelphia County (up 22%), Fulton County (Atlanta), Ga. (up 22%); Travis County (Austin), Texas (up 20%), and Contra Costa County, Calif. (outside San Francisco) (up 19%).

In 92% of markets, price appreciation rose more than wage growth. The largest counties where that occurred included Los Angeles County, Cook County (Chicago), Harris County (Houston), Maricopa County and San Diego County.

In only 25% of the 499 markets in the report could someone making $75,000 afford the typical home in Q4. Fifty-five percent of counties were less affordable in Q4 than their historic affordability averages, which is an increase from 43% in Q4 2019.

Other indicators are also showing that for-sale housing is becoming more unaffordable for Americans.

For the four weeks ending December 20, the median home sale price increased 14% year over year to $320,714, according to Redfin. In July, the median home price was $300,462. 

If the trend persists, it could keep more people in rentals.

The combination of scarce housing, low-interest rates, plus very strong demand “has pushed home prices to levels that are making it difficult to save for a payment, particularly among first-time buyers, who don’t have the luxury of using housing equity from a sale to use as a down payment,” said Lawrence Yun, the National Association of Realtors’ chief economist.