The vast majority of Americans, 78 percent, say they're "extremely" or "somewhat" concerned about not having enough money for retirement, according to Northwestern Mutual's 2018 Planning & Progress Study. And for good reason: A shocking 21 percent of Americans have nothing at all saved for the future, and another 10 percent have less than $5,000 tucked away, the study finds. That means about a third of Americans have only a few thousand dollars, or less, put away for their golden years.