(The Hill) — Fewer Americans are moving to new homes than at any time since the government began keeping track, as demographic trends collide with a hot housing market in which prices are rising over lack of supply.

New data from the U.S. Census Bureau shows just 8.4 percent of Americans live in a different house than they lived in a year ago. That is the lowest rate of movement that the bureau has recorded at any time since 1948.

That share means that about 27.1 million people moved homes in the last year, also the lowest ever recorded.

The number of Americans who move from one home to another has been falling for decades, said Cheryl Russell, who authors the Demo Memo blog on demographic trends. In the 1950s and 1960s, about one in five Americans moved homes in a given year. That dropped to 14 percent by the turn of the century, and to 11.6 percent a decade ago.

The more sedentary population is a product of a handful of demographic factors that have grown as the American population gets older, as fallout from the Great Recession a decade ago continues to play out and as the pandemic put the brakes on many people’s plans.

Edward Berchick, a senior population scientist at the online real estate firm Zillow, said all of those factors have contributed to fewer home sales.

Older people tend to move less. And as fewer Americans have children — the birthrate also stands at an all-time low — fewer families feel the need to move into larger homes. The pandemic also injected caution into buyers’ minds as they sheltered in place to protect themselves from the virus.

“Right now there’s a lot of uncertainty about longer-term plans,” Berchick said. “With some economic uncertainty, people just pause their plans.”

The aging population is playing a significant role. Never before has the United States had so many residents over the age of 65 — an age when people are most likely to own their own home, and least likely to face pressure to move somewhere new.

“Aging boomers are clinging to their homes, as is typical of older Americans,” Russell said in an email. “Boomers are in the lifestage where people typically stay put. With older Americans increasingly dominating homeownership, the top-heavy age structure has reduced inventory and dampened mobility.”

At the same time, those who are looking for a home are encountering some of the highest prices ever recorded. Zillow data shows the typical home value stands at $312,000, up 19 percent over the last year and forecasted to rise another 13 percent in the coming year.

Prices are rising not only in big cities like New York, Seattle, San Francisco and Washington, D.C., but in smaller mid-level metropolitan areas as well. Data compiled by Realtor.com, an online real estate listing agency, found the hottest markets in the United States are in Manchester, N.H., Burlington, N.C., east of Greensboro, and Eureka, Calif.

Three cities in Indiana — Elkhart, Lafayette and Fort Wayne — are also among the hottest markets in the nation.

The rising prices mean those who are looking for a home are entering a market in which their dollar does not go as far as it once did. An ongoing home shortage, and construction that slowed during the pandemic in part because of supply chain and workforce issues, has put more upward pressure on those home prices.

Census Bureau data shows the total number of housing units grew by just 6.6 percent between 2010 and 2020, while the number of vacant units dropped by 8.6 percent, a sign of a market that is tightening rather than expanding.

“In the last several decades, population growth has outstripped growth in the housing supply,” Berchick said.