Lower mortgage rates are the one thing that could draw buyers back into the housing market, according to a new survey from Realtor.com. The magic number? Around 5%.

Approximately one-fifth of Americans say buying a home would be possible in the next year if rates fall below 6%. An even larger proportion — about one third — say rates would need to drop below 5% for their homeownership dreams to come true.

“Small changes in mortgage rates indeed have an outsized impact on monthly mortgage payments,” Danielle Hale, chief economist at Realtor.com, said in the report. “For first-time homebuyers, if mortgage rates drop in the [5% range], that will boost their purchasing power. For a lot of repeat buyers who already own a home, the lower rates go, the less of a jump they will take in their mortgage payments.”

Mortgage rates have been steadily falling since they neared 8% last autumn. However, they’ve yet to drop below the mid-6% range.

“Mortgage rates are down more than a whole percentage point from their peak,” Hale added. “For the same monthly payment, you can afford to purchase a more expensive home or you have a lower monthly payment at the same home price. Either way, it’s a win for the buyer.”

Despite this, many would-be homebuyers say they’d be willing to purchase a home even if rates don’t continue to drop. Almost half of millennials and over a third of Gen Z say they’d buy a home even if rates exceeded 8%.

Younger buyers are also the most optimistic — almost half of Gen Z buyers surveyed said they’d be able to afford a home in the next five years, compared to 32% of millennials, 36% of Gen X and 26% of Baby Boomers.

“It makes sense that younger buyers are more optimistic,” said Hale. “There are certainly more challenges; they tend to have lower incomes and lower savings. But they’ve also got their whole life in front of them. With incomes now outpacing inflation, we’re looking at real increases in their purchasing power.”