(Bloomberg) -- The scarcity of existing houses is so severe in the U.S. that a record share of available properties are now newly built. 

About 34% of the country’s single-family inventory in December was new construction, up from 25% a year earlier and more than twice the historic average, according to an analysis by Redfin Corp. 

Builders are stepping up production despite supply-chain snarls and rising labor costs. But it’s not enough to make up for the extraordinary scarcity of previously owned houses.

Newly built homes have made up an increasingly big chunk of the housing supply over the past decade and their share shot up in mid-2020 after the pandemic caused a stampede to the suburbs.  

Purchases of new single-family homes jumped to a nine-month high in December while the inventory -- including lots and houses in various degrees of completion -- rose to 403,000, the most since August 2008, government data show.

Meanwhile, the supply of existing houses listed for sale plunged to 780,000, the lowest level in history and down 11% from a year earlier, according to the National Association of Realtors.

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