New York City’s housing crunch is the worst it has been in more than 50 years.

The portion of rentals that were vacant and available dropped to a startling 1.4 percent in 2023, according to city data released on Thursday. It was the lowest vacancy rate since 1968 and shows just how drastically home construction lags behind the demand from people who want to live in the city.

Housing experts often consider a “healthy” vacancy rate to be somewhere around 5 to 8 percent. A higher vacancy rate typically means it is easier for people to find apartments when they want to move. It also means that property owners are more likely to have to compete for renters, conditions that would moderate rent increases.

The data suggests New York City’s housing crisis is only getting worse. The 1.4 percent rate was down from 4.5 percent in 2021, the last time the survey was conducted. New York officials consider a vacancy rate of less than 5 percent to be a “housing emergency.”

“The data is clear: The demand to live in our city is far outpacing our ability to build housing,” Mayor Eric Adams said in a statement announcing the numbers on Thursday. “New Yorkers need our help, and they need it now.”

The scale of the problem is putting more pressure on officials to do something about it. High housing costs continue to force families and working class people out of the city, threatening the economy. An influx of migrants has overwhelmed the city’s homeless shelter system, and homelessness among non-migrants is also on the rise.

Housing experts estimate that the number of homes the city needs to build is in the hundreds of thousands. But New York City has issued fewer building permits per resident than Boston, San Francisco and Austin, Texas, over most of the past decade, according to the Citizens Budget Commission, a nonprofit watchdog organization.