Less than half of Americans say they expect to have enough money in retirement

Thoughts of retirement might leave some daydreaming about relaxing their golden years away. But for others, it can trigger anxiety and fears about even being able to afford it.

Less than half of Americans who are still working (45%) believe they will have enough money to live comfortably when they retire, according to new Gallup polling .

But those pessimistic workers might be presently surprised when the time arrives; the survey also found that three in four retired Americans (74%) say they have enough money to live comfortably.

The disconnect between retirement expectations versus reality has persisted "as far back as Gallup has data" and has several possible explanations.

"Retirees may take unanticipated advantage of the opportunities to downsize and move to cheaper areas of the country, and they may have unanticipated lower daily expenses in general without work or childcare responsibilities. Medicare may help cover healthcare costs in ways not anticipated, even if they have greater healthcare needs in retirement than they did before," Frank Newport and Jeffrey M. Jones wrote in an analysis for Gallup .

The reality versus expectations gap can also be explained by the unanticipated value of Social Security in retirement.

Gallup's polling shows most working Americans anticipate funding their retirement mainly with 401(k)/IRA/retirement savings account (50%), followed by Social Security (35%), savings from savings accounts or CDs (24%), equity built up in home (23%), and work-sponsored pension plan (22%).

In reality, the polling shows 58% of retired Americans say Social Security is a major income source of their retirement income, followed by work-sponsored pension plan (34%), 401(k)/IRA/retirement savings account (29%), equity built up in home (20%), and individual stocks or mutual funds (17%).

Most Americans expect they will have other sources of income outside of Social Security. But even among the 23% of retirees who say their only major income source in retirement is Social Security, 60% say they have enough money to be comfortable.

That should be enough to quiet some of the financial fears of working Americans. But there's yet another disconnect: while retirees heavily rely on Social Security, Gallup says non-retirees have a strong lack of confidence in the long-term viability of the system.

"Only about half of non-retirees Gallup interviewed last June and July say they expect the Social Security system to pay them a benefit when they retire," Newport and Jones noted. Another study found that 80% of Americans age 62 and under are worried that Social Security will not be available when they are eligible to receive it, up from 75% two years ago.

The major recommendation from Gallup is a continuing focus on maintaining Social Security's viability.

"Although Social Security is clearly not a total solution to financial security in retirement, retirees have continually over the past 23 years listed it as their most important source of retirement income," Newport and Jones wrote. "The government can profitably, the data suggest, engage in a two-pronged strategy: maintain Social Security at all costs and continue practical and motivational efforts to encourage non-retirees to build retirement accounts."