Outliving savings is the major fear regarding retirement among all age groups and is especially a concern among younger workers, according to the TransAmerica Center for Retirement Studies, which conducted a phone survey of more than 4,500 workers about evenly split among age groups by decade.

It found that was the number one fear among 48 percent of those in their twenties and 46 percent of those in their thirties, potentially reflecting the decline in defined benefit retirement plans available to those entering the workforce in recent times compared with decades ago. In contrast, that is the top fear of only 44 percent of those in their fifties and 42 percent of both those in their forties and those in their sixties.

The second largest fear is that Social Security will cease to exist, with those in their thirties having the greatest concern and those in their sixties having the least, 40 to 26 percent.

Other major concerns include declining health that requires long-term care, with older groups tending to be more concerned—although as many of those in their twenties expressed that fear as those in their sixties, 38 percent.

Among all age groups, the lowest levels of concern involved finding meaningful ways to use their time and stay involved; feeling isolated and alone and inability to retire on their own terms.

Among all groups, the top retirement dream was travel, followed by spending more time with family and friends and pursuing hobbies, with relatively little variation.