NEW YORK (CNN/Money) - Despite increased efforts by employers to encourage workers to save for retirement, young employees continue to ignore their 401(k) plans and participation rates overall improved only slightly in the past few years, said a study released Tuesday.

The study, conducted by global human resources firm Hewitt Associates, found that only 46 percent of workers under the age of 30 participated in their company's 401(k) plan.

Moreover, the participation rate among the more than 2.5 million eligible employees surveyed increased just 2.1 percent between 2002 and 2004 to 70.3 percent.

"Despite all the attention around retirement, it's discouraging to see that many people -- especially younger workers -- still do not feel a sense of urgency to take control of their financial security by investing proactively in their 401(k) plans," said Lori Lucas, director of participant research at Hewitt Associates.

Of those who did participate, nearly one in four had a balance of less than $5,000, and the average 401(k) balance reached $69,000, said Hewitt.

The study also found that one in three people put in just enough to obtain the full company match, and that 22 percent of participants did not contribute even enough to obtain the match.

"Employees who do not contribute enough to receive their employer's full matching contribution are leaving free money on the table," said Lucas.

"Even those who contribute enough to obtain the full company match may only be contributing 3 - 4 percent of pay... This may be far too low to ensure financial security," she added.