For middle-class Americans, retirement simply means a new phase of their working years, according to results from the sixth annual Retirement Fitness Survey from Wells Fargo & Co.

The survey found that 72 percent of middle-class Americans between the ages of 25 and 69 expect to work through their retirement years. The trend is driven both by deep deficits in personal retirement savings—39 percent said they will need to work to make ends meet or maintain their lifestyles—and also by lifestyle choice, with 33 percent saying they will continue to work because they want to.

Middle-class Americans, especially those under 50, increasingly know that retirement is a do-it-yourself endeavor, judging by the study data.Only 40 percent of those surveyed said they think Social Security will be available throughout their retirement, including only 20 percent of 20-somethings and 22 percent of 30-somethings.All five generations surveyed voiced strong support for changes in 401(k) plan design and regulation that would enable more guidance and advice to help people to save more.

While many Americans express worry about their retirement prospects, judging from their finances, they probably aren't worried enough, the survey suggested. Respondents predicted they will need a nest egg of $300,000, but have saved just $20,000 of that amount for retirement (figures throughout were medians, the midpoint of responses).They said they expect to live on retirement savings for nearly two decades (19 years), while planning to spend 10 percent of their nest egg every year. The industry recommendation is to withdraw no more than 4 percent annually.

The median retirement savings of respondents age 50 to 59 is $29,000. Stretched out to fund a retirement of 20 years, these savings would amount to about $190 a month, assuming a 5 percent rate of return. Yet, 56 percent of the 50-somethings say they are "confident or very confident" they'll have the money they need to support their desired lifestyle throughout retirement.

"Too many Americans have their heads in the sand in the face of obvious savings deficits," says Laurie Nordquist, director of Wells Fargo Institutional Retirement and Trust. "People are not even close to where they need to be in total savings.Barring a miracle, a winning lottery ticket or a big inheritance, they're going to be forced to dramatically cut back their lifestyles after retirement."

Nordquist noted, though, that there is one bright spot.

"Americans seem to get that retirement planning is now in their hands, which is a start in terms of taking control," she says.

On behalf of Wells Fargo, Harris Interactive Inc. conducted more than 1,700 telephone interviews of middle-income Americans in their 20s, 30s, 40s, 50s, and 60s, surveying attitudes and behaviors around planning, saving, and investing for retirement.

Other top findings include the following:

•20-somethings are the least confident about investing in the stock market and are most likely to put their savings in a bank certificate of deposit rather than invest in stocks.

•40-somethings are under the most financial stress of any age group. They are dramatically less likely to have pensions than older workers, and economic strains are most likely to be causing tension in their households. About 80 percent of them expect to work through retirement, versus 54 percent of 60-somethings.

•Those surveyed expressed strong support for reforms that would encourage additional saving. Respondents overwhelmingly (79 percent) said they want employers to offer more advice to help manage their retirement plans—guidance that is difficult for employers to provide under current regulations.

•Only a third of those surveyed have a detailed written retirement plan.

•Compared with Americans who are married or partnered, single people who were surveyed said they are more confident in the future of Social Security and expect to spend less on health care during retirement.

•Two-thirds of respondents said they believe they should be saving more and could be if they got more guidance or advice.

"People in their 50s and 60s are the last generations that can depend on traditional pensions, and their confidence level as they approach retirement reflects that," says Joe Ready, director of Wells Fargo Institutional Retirement and Trust. "In the younger age groups, we're seeing that individual savings efforts, whether through 401(k)s or IRAs, are much more important than to older generations, most likely reflecting the reality that they know they are responsible for their own retirement."

Respondents expressed strong support for a number of measures that would enable and encourage additional saving. Asked whether employers should provide more personal advice services to help employees manage their 401(k)s, 79 percent of respondents agreed. A similar majority (82 percent) agreed that employees should be offered a lifetime income option in their retirement accounts, which could be more prevalent with clearer regulatory guidelines.

Two-thirds expressed agreement that, for those without access to a 401(k) or similar plan, an equivalent system should be created. Of those with a 401(k) and company matching contribution, 85 percent said they contributed as much as their company will match, suggesting this is an effective incentive.

When asked about the impact of the recession on their financial management and retirement expectations, 71 percent of those surveyed said they are actively working to reduce debt.

Two-thirds of respondents said they're not very confident or not at all confident that the stock market is a place for investment gains for their savings, and 55 percent say they have other financial priorities and don't have extra money to save.

Also, one-third of respondents said they are worried about a job loss in their household in the coming year, with forty-somethings (43 percent) and 50-somethings (42 percent) being the most worried about that possibility.

Finally, the survey found that people making $75,000 to $100,000 a year have outsaved those making $100,000 and up, with a median of $99,000 in total investable assets versus $59,000 saved by those making $100,000 and up.