Americans can be saving more for retirement, but instead they don’t put as much into their employer-sponsored retirement plan as they can. And when they do they rely on their gut when deciding how much to contribute, according to an ING Retirement Research Institute survey released on Friday.

Even though Americans know they are responsible for their retirement and are not confident about the future of Social Security they still save less than they know they should.

So, what’s the problem?

Yes, individuals recognize the need to save for retirement but it has not led them to save more. Not only that, but many fail to increase their contribution rates to their retirement accounts, even when they know they can.

The ING survey, which was conducted with 1,000 workplace retirement plan participants between Sept. 24 and 28, 2010, found that 87% of workers said they could save more in their employer-sponsored retirement plan. Sixty-four percent said their workplace retirement accounts make up all or most of their retirement savings. And 44% admitted that if they didn't have a retirement plan at work, they probably wouldn't be saving for retirement at all. Yet those surveyed said they relied on “guesswork” to set their contribution levels.

“Americans today understand that they shoulder a greater responsibility for securing their own retirement,” said Rob Leary, CEO, ING Insurance U.S., in a statement on Friday. “They also recognize that an employer-sponsored retirement plan is the cornerstone of their efforts to save for retirement. Still, the issue for many workers, made even more urgent in shaky economic times and an era of volatile equity markets, is scrubbing household budgets and, when possible, finding more dollars to save for retirement. Being cost-conscious is certainly important and prudent, but at the same time, people must also find ways to contribute more into their retirement accounts.”

ING found that of those participants not contributing the maximum to their retirement plan, 87% admitted they could afford to increase their annual contribution by 1% of their annual salary, while 59% said they could increase their contribution by 3% of salary and 32% said they could afford a 5% increase.

Not only that, but most workers didn’t consult any outside sources before setting their contribution levels. Sixty-five percent determined their contribution rate themselves, and 21% said they “go by gut feeling.”

“After choosing to participate in the plan, the most important decision workers make is setting their contribution rate each year,” said Catherine Smith, CEO, ING U.S. Retirement Services, in Friday’s statement. “However, for too many, participation and contribution rate elections are just another box to check. We need to be more deliberate and take the time to consider things like tax impact, compounding, and the effects of employer matches in making these elections.”