New York ? Battered by three years of stock market declines and the weak economy, Americans have become less optimistic about their ability to accumulate enough money to retire comfortably.

A survey released Friday found that 21 percent of workers were very confident about having enough money to fund their retirement. That was down from 23 percent last year and the lowest reading since 19 percent in 1996.

Those who said they were not at all confident of having sufficient funds jumped to 16 percent in 2003 from 10 percent last year.

The findings are part of the Retirement Confidence Survey, which is conducted annually by the Employee Benefit Research Institute, the American Savings Education Council and market research firm Mathew Greenwald & Associates Inc. All are based in Washington, D.C.

Dallas Salisbury, the chief executive of EBRI, said that the discomfort Americans are feeling about their retirement preparedness may be a good sign.

“It tells me that people are getting far more realistic about the world as it exists,” he said. “The bubblish optimism is a thing of the past.

“I think people are beginning to realize that if they want enough for retirement, they’re actually going to have to save for it — and save more,” Salisbury said.

Perhaps the most startling statistic is that one-third of workers 45 and older say that in the past year, they’ve changed the age at which they expect to retire, with most anticipating they’ll have to work longer.

The study said they blamed such factors as stock market losses, the rise in the eligibility age for Social Security and concerns about higher living costs.

Twenty-five percent of workers surveyed said they expect to retire at 65 and 24 percent expect to retire at 66 or older. Six percent expect never to stop working and the rest intend to retire early, the study found.

Salisbury warned, however, that people hoping to compensate for a lack of saving by working longer may find that impossible.

“When you ask people who are actually retired, 40 percent left the work force earlier than they thought they would,” he said. “Some had medical problems, some were downsized or their factories closed.”

There also was a disconnect in how workers expect to fund their retirement.

Workers said they believed most of their money would come from a company pension and their personal savings, followed by Social Security and a company-sponsored retirement savings plan such as a 401(k), the study found. Retirees, however, said the bulk of their income came from Social Security, followed by pensions and private savings.

The 2003 survey found that 68 percent of workers say they have saved for retirement, up from 67 percent in 2002 but down from a peak of 74 percent in 2000.

The survey of a random sample of 782 workers age 25 and older and 218 retirees was conducted by telephone in January. It has a margin of error of plus or minus 3 percentage points.