A recent NerdWallet survey finds that 22% may be the new threshold for working Americans ages 18-35 as analysts predict slow economic growth following the Great Recession will diminish returns from 7% to 5% in the coming decades.

As a result, a 25-year-old who earns $40,000 a year now will need to have saved 22% of of their earnings in a retirement account to account for 80% of their income by age 67, according to a NerdWallet.

Millennials commonly put off retirement savings because they’re burdened by hefty student loan debt, the site notes.

“If these lower returns become a reality, it will be that much harder for those who put off investing to catch up, “investing and retirement specialist Arielle O’Shea said via press release. “The best thing Millennials can do is invest as much as they can as soon as they can.”

Those who put it off till they’re 35 or older can suffer serious consequences going forward. They’ll be forced to save a hefty 34% of their annual income to retire and match 80% of their income at age 67.

“Millennials need to focus on controlling what they can control,” O’Shea said, “saving as much as they can, taking an appropriate amount of risk for their very long time horizon, keeping their investment expenses low, and grabbing all available tax advantages.”