A Fidelity Investments survey indicates that more than half of current workplace investors wouldn't be saving for retirement if not for their 401(k) plan.

The survey also indicated that while many workers have increased their contribution rates, most said that they wish they could save more.

The survey, released today, highlighted the savings behaviors of current and former 401(k) participants. Fidelity surveyed 1,000 current and retired workplace 401(k) plan participants in the U.S.

Nearly one in five respondents currently enrolled in a plan say they have no retirement savings at all outside this key retirement benefit.

"This research helps us better understand how Americans use their 401(k) to help achieve their long-term retirement savings goals," said James M. MacDonald, president, Workplace Investing, Fidelity Investments. "It also provides an interesting snapshot of the actions of workplace plan participants in an uncertain economic climate."

An estimated 90% of survey participants said they participated in a 401(k), so as not to lose out on company matching dollars. Roughly 90% of participants also said a 401(k) plans is a good tax-deferred way to save.

However, economic conditions still present a challenge for many, with over 50% of survey respondents saying they would contribute more to their 401(k) if they could.

Fidelity in May reported that nearly one in ten corporate defined contribution participants increased their contribution rate during the first quarter of 2011, the largest percentage to do so since Fidelity began tracking corporate contribution figures in 2006.

The survey also found that 53% of respondents said they've increased their 401(k) contribution rate in the last five years, despite market volatility and economic uncertainty. When asked why they increased their contributions, 23% of respondents said they wanted to take advantage of employer matching dollars, while 38% said they had received a raise or had extra money available to invest.

Twenty-three percent of respondents reported that they had at one time decreased their workplace plan contribution percentage. For those who decreased contributions, 46% reported they needed extra money while 9% said they decreased it due to elimination of a company match. An estimated 40% of these respondents said they already do-or possibly will-regret the decision to decrease their retirement savings contribution.

To supplement their workplace plan, 37% of respondents indicated that they are also building retirement savings in an IRA. In addition, 33% are in an employer-sponsored pension plan, 28% have savings in bank accounts, and 28% have investments in stocks or bonds. Pre-retirees 55 and older are the most active users of IRAs, with 44% saying they utilize these retirement savings investments.

-Jim McConville