Four of five Americans are expected to fall short of meeting all of their financial needs in retirement unless they improve their savings habits or retire at a later age.

According to a study by Hewitt Associates, a global human resources consulting and outsourcing services company, employees will need 15.7 times their final pay when factoring in inflation and postretirement medical costs.

Although this estimate is on target with Hewitt’s prior projection in 2008, many employees find themselves in a tougher financial situation because they’ve seen their retirement accounts decrease over the past two years, the studey released Monday said.

Of the 15.7 times final pay, Hewitt estimates that Social Security will provide 4.7 of it, leaving employees responsible for making up the remaining 11 times final pay. This will likely have to come from company-provided plans and personal savings, but of the more than 2 million employees at 84 large U.S. companies it examined, Hewitt’s study found that only 18% of these people who are expected to work a full career will meet this goal.

On average, employees are projected to accumulate 13.3 times their final pay with Social Security, leaving a shortfall of 2.4 times pay.

Workers who rely solely on a defined contribution plan to fund their retirement are expected to meet just 74% of their financial needs in retirement. Workers who are also covered by an active or frozen defined benefit plan are projected to meet 74% of their retirement needs.

Hewitt recommends three steps employees can take to curb their savings shortfall: Start saving, regularly increase contribution rate and work longer. Byron Beebe, the U.S. retirement market leader at Hewitt, said companies that auto enroll into a retirement plan have a 90% participation rate on average, but employees often run into inertia.

“If employees are enrolled at 3%, we’ll find that three years from today they will still be at 3%,” Beebe said. “That’s why we have been talking to more and more employers about auto-escalation.”

He added that employees will often stop increasing their contribution once they reach the company’s maximum match level. This often means that workers are stopping at 6%, for example. Hewitt, meanwhile, recommends the contribution level be at double digits.

The good news is that over the last five years or so, Hewitt has seen the retirement age continue to rise. Part of the reason is that fewer employees took voluntary retirement in 2008 and 2009 because their account balances declined during the recession. Beebe said employees should proactively calculate how much money they will need during retirement in order to make better decisions about how much they contribute to their company retirement plan, or how long they decide to work.

“They should start to do these calculations on their own,” he said. “People have in their mind an age for their retirement. But if people start looking at their numbers they will be shocked.”