The survey findings by the Pew Research Center reflect the impact of a weak economic recovery that has shown stock market gains while housing values remain decimated.
As a whole, retirement worries rose across all age groups. Roughly 38 per cent of adults say they are "not too" or "not at all" confident that they will have enough for retirement, up from 25 per cent in 2009.
Pew found that retirement worries peaked among adults in their late 30s. Three years ago, it was boomers ages 51 to 55 who had the most anxiety.