It's clear in my conversations with investors that while memories are short when it comes to investing, few have forgotten the stock market's twists and turns of 2008 and early 2009. But the latest report from the Investment Company Institute and the Employee Benefit Research Institute may surprise some investors. In 2009, 401(k) balances were up about 32 percent. And despite the terrifying events of 2008, where the average 401(k) participants' account balance dipped 27.8 percent, the average return over the past six years was 10.5 percent, with accounts averaging $109,723 at year-end 2009. That's up from $61,106 at year-end 2003.

The ICI/EBRI study looked at 4.3 million consistent 401(k) account participants who have had account balances from year-end 2003 through year-end 2009.

During the webinar held to go over the data, one reporter asked why the report started at year-end 2003. Had it gone back to 2001, the numbers would tell a less cheery story. An EBRI spokesman responded that the sample of consistent participants was too small if it went beyond 2003.

Yikes. This is the second report in as many weeks essentially implying that 401(k)s are working to build retirement riches for employees. The first was a Fidelity report saying that thanks to consistent contributions from employers and employees, pre-retirees - workers 55 and older - saw their 401(k) balances double over the past decade.

But the fact that so few workers have consistent 401(k) balances is depressing. Sure, it's hard to say why there isn't consistent participation. Maybe it's because workers like me switched jobs along the way, but invested the entire time. Or it could be that the economy took its toll and when times are tough, retirement savings suffers. Or life expenses just consume too much of the average family's money, especially when incomes are stagnant or falling.

Either way, I keep thinking back to a smart post over at moneywatch.com written by the site's editor-in-chief Eric Schurenberg. No matter which way you look at it or what data you choose to use, 401(k)s simply are not growing fast enough to afford workers a 30-year vacation.