While what teens don't know about money gets the most attention, financial literacy is a problem across age groups.

There is some momentum building to increase the teaching of personal finance in K-12 schools. That may help younger Americans, but what about those soon-to-be or already retired?

A huge amount of wealth and well-being is at stake. Spectrem Group calculates that U.S. retirement assets increased in 2009 to $9.3 trillion from $7.9 trillion the previous year.

But I'll tell you right now that getting smarter about investing had little to do with it. The rising markets of 2009 lifted the rust bucket we call our retirement system.

For those in retirement, there's precious little impartial advice on how to draw down the assets that people accumulated over a lifetime of work. The answer, of course, is different for every individual, and it's closely related to making sure retirees don't outlive their funds.

Most of us fail to do any kind of retirement planning, even though we're scolded to do just that, and plenty of books, articles, and online calculators could provide some guidance.

A little planning for the future can help nail down key assumptions all of us should make. At what age will I retire? How much will I spend yearly as a retiree?

But as Wharton professor Olivia S. Mitchell notes, many of us have peculiar notions of time and our journey through it. Getting "old," like tomorrow, never comes.

"No one wants to think of themselves as getting old," Mitchell said. No matter what age you are, she said, being "old" remains a stage of life that's "20 years older than you are."

By delaying that reality check, people are also not confronting the likelihood of outliving their savings. Mitchell, who is also executive director of Pension Research Council, said actuaries 30 years ago considered 100 to be the outermost age for planning purposes. Today, it's 120 years. Can you imagine retiring at 62 and living off your assets for six more decades?

Mitchell and Dartmouth College economics professor Annamaria Lusardi have documented low levels of financial literacy among all age groups, especially those over age 55. According to U.S. Census estimates, there were 72.6 million people in that age group.

The researchers analyzed 2008 data from the University of Michigan Health and Retirement Study, which has been collecting data every two years since 1992. They found that older adults lacked a "rudimentary understanding" of stock and bond prices, diversifying investment risk, and how investment fees affect wealth.

For instance, the survey asked about the inverse relationship between interest rates and bond prices. When interest rates rise, bond prices tend to fall. Multiple surveys have shown fewer than half of respondents understand that.

As Mitchell and Lusardi found in their previous work, older women were less likely than older men to say they understood the stock market well. But as the October 2009 paper points out, even people who correctly answered a particular question testing their financial knowledge weren't likely to get others right.

Contact Mike Armstrong at 215-854-2980 or marmstrong@phillynews.com. See his blog at www.phillyinc.biz and Philadelphia Business Today Webcast at www.philly.com/business.