Although housing inventory may be a little slim these days, Zillow says it expects for Baby Boomers to open the housing market back up as they vacate their homes over the next two decades.

About a third of homes in the U.S. are owned by those who are 60 and older. In the 2020s and 2030s, Zillow expects this generation will create a “Silver Tsunami,” allowing for more homes on the market as they move out of those homes.

And according to Chase, 76% of Baby Boomers own their own homes.

Between 2007 and 2017, Zillow says nearly 730,000 U.S. homes were released back into the market each year by seniors age 60 or older. From 2017 to 2027, that number is expected to rise to 920,000 and 1.17 million per year, respectively.

Basically, more than 27% of today’s owner-occupied homes will be available by 2037.

Housing released by the “Silver Tsunami” is expected to reach as many as 20 million units. Zillow says this could be a similar event to the new home construction during the 2000s boom-bust cycle.

It’s become more popular for Boomers to stay put, get a roommate and or even downsize to be able to afford housing, all to be able to age in place.

And as there are more Boomers living in single-family homes, retirement communities are also expected to see a drop in residents over the next 20 years.

Boomers have created what seems like a gridlock in the housing market by staying in place, but that could begin easing soon.