Home sales dropped in September to the lowest level since the foreclosure crisis as surging interest rates and climbing home prices made buying a home unattainable for a growing share of would-be buyers.

According to the National Association of Realtors, historically low inventory has pushed prices up and rates have crossed 7% in August, pulling sales to their lowest level in 13 years.

Last month, the median price of existing homes – which includes single-family homes, townhomes, condominiums, and co-ops – was $394,300. Those prices were up 2.8% from a year ago and marked the third consecutive month of year-over-year price increases. The NAR report found that prices rose in all four regions of the country, the Northeast, Midwest, South, and West.

“Home prices have risen for the third consecutive month, confirming the need for more housing supply,” said Lawrence Yun, NAR chief economist.

As a result of low inventory and high prices, existing home sales dropped 2% from August to September, to just above analysts’ predictions of 3.96 million units.

Annually, September sales were down 15.4% from a year ago, when 4.68 million units were sold.

Affordability remains a challenge for many buyers, but the difficulty of finding a home is also affecting sales.

The majority of homeowners with mortgages have rates at or below 6%, according to ICE Mortgage Technology, which recently acquired Black Knight. As a result, homeowners cannot sell their homes and are forced to borrow at today’s average interest rates of over 7%. One region, the Northeast, actually saw an increase in home sales.

Many people remain unable to afford to buy a home, so analysts wonder if this is a temporary phenomenon or if homeownership is about to enter a new era.

Besides excluding people from homeownership because of high costs, the composition of those who remain in the market is changing as well.