A new study by the Employee Benefit Research Institute suggests that almost half of baby boomers will have trouble paying for basic expenses and uninsured health costs after retirement. The study estimates that 47% of baby boomers between the ages of 56 and 62 will come up short of the cash needed to pay for these expenditures.

On the other hand, seven years ago in 2003, an estimated 59% of boomers were expected to run short, a much higher value than today. So what’s changed since 2003? A broader use of policies governing work-based retirement plans like automatic enrollment in 401k plans ensure that more is available to workers for retirement living expenses.

“This makes a huge difference, especially for low-income workers,” said the study’s coauthor, Jack Vanderhei, research director of EBRI.

However, every individual is somewhat responsible for maintaining their own expenses based on factors like how much they make presently and the amount of time their will spend in retirement.

For instance, people making roughly $31,000 to $72,000 a year today have a 13% chance of not being able to pay all their expenses after 10 years in retirement and a 29% chance after 20 years. So of course those making less than $31,000 a year will are at much higher risk of running out of money too soon. Even some of those in a higher income bracket of over $72,000 who are expected to have the most money in retirement will be scrambling to make their financial obligations.

The main offender? Uninsured health costs.

“Nursing home costs are wiping them out,” Vanderhei said.

The solution to this problem? Boomers are going to have to save more, but how much more? That depends entirely on how much you’ve got in your bank account, how many years until you retire, your expected Social Security and pension benefits, and how much return you’ll get off your investments.