Retirees are about as inaccurate as older active workers when it comes to estimating how long their retirement years are likely to last.

Ameriprise Financial Inc., Minneapolis (NYSE:AMP), has published figures supporting that conclusion in a summary of results from a May survey of 2007 U.S. adults ages 40 to 75 and a similar survey conducted in August 2005.

Pre-retirees estimated retirement would last 19.6 years; retirees estimated retirement would last 19.8 years.

Experts suggest that most married couples should assume retirement will last at least 30 years.

The U.S. Bureau of Labor Statistics has estimated that, if one spouse in a couple is 65, there is a 50% chance that at least one spouse will live to age 92.

The pre-retirees might be saving more: The percentage saying they are saving increased to 87% in May, up from 82% in 2005.

The percentage who say they are working with a financial advisor has increased to 43%, from 37%.

-wh