Americans had better hope that Social Security doesn’t go broke, because few of them have given much thought to retirement.

Less than a third of non-retired investors  have given “a lot of thought” to the best age for retirement, while 11 percent say they have given it no thought and 31 percent have thought about it only a little, according to a survey by Gallup.

“Even among those aged 50 and older, only 39 percent have thought about it a lot, while 29 percent have thought about it only a little or not at all,” the polling company said.

The lack of preparation for retirement may result in profound regrets for investors. Among retired investors included in the survey, 52 percent say they wish they had started to think about the best age to retire earlier.

Not surprisingly, people who have planned ahead also have more money in the bank.  

“Of those who currently have less than $100,000 in investments, 19 percent have thought a lot about the best age to retire,” Gallup said. “Among those with $100,000 or more invested, 37 percent have thought a lot about when to retire.”

The data come from the Wells Fargo/Gallup Investor and Retirement Optimism Index, conducted February 10-19. The index is a survey of U.S. investors who report having $10,000 or more in stocks, bonds, mutual funds or an individual retirement agreement or 401(k). "Non-retired investors" includes all respondents in the survey who identify themselves as not retired, including students, homemakers and those seeking work.

“Most U.S. investors -- regardless of age or investment value -- have not given a lot of thought to when they will retire, nor have many read up on retirement-age considerations, reviewed the Social Security Administration's website or talked about retirement age with a professional financial adviser,” Gallup said. “Even among those aged 50 or older, only about half of U.S. investors have taken these steps.”

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