Affluent Americans may not be as ready for retirement as they believe, according a new survey from Charles Schwab & Co.

The survey found that while most affluent Americans have a retirement plan in place (84%) and feel confident about their retirement readiness (80%), they may be underestimating how much money they will need once they retire. Survey respondents estimate they will need on average about $66,000 in annual income, significantly less than their current average income of $115,000. 

“In many cases, we tell clients to assume they’ll need roughly the same annual income in retirement as they had beforehand unless they anticipate a significant lifestyle change, and to take into account longevity risk when planning how much money they might need,” Carrie Sxhwab-Pomerantz, senior vice president of Charles Schwab, said in a statement.

Almost four in 10 affluent Americans (39%) said they do not plan to work at all in retirement and 46% said they might work part-time even though they expect to have enough money to live without working. One in 10 believed they will have to work at least part-time to make ends meet, according to the survey.

For roughly half of the respondents (52%), confidence in their retirement readiness was unchanged from last year. Almost as many felt more optimistic (23%) as they did less optimistic (24%) about their retirement readiness than a year ago.

Respondents did express some financial worries. More than half (53%) said their primary concern is incurring unexpected expenses in retirement, such as medical or healthcare costs.

The study polled 1,811 investors between the ages of 25 and 80 with a minimum of $250,000 in investable assets and retirement funds. It was conducted between January 14, 2013 – January 25, 2013 by Koski Research.