It has been more than two decades since the tax-advantaged 529 plan was created, but even though college tuition has continued to rise since then, Americans are still largely oblivious to the savings tool, a new survey says.

A survey of about 1,000 U.S. adults in April commissioned by Edward Jones found that U.S. residents have actually shown a decline in knowledge about 529 plans: 67 percent of respondents didn't know anything about the tax-advantaged college-savings plans, up from 62 percent in 2012.

Of those who correctly identified a 529 plan as an education savings vehicle, 48 percent—including 50 percent of parents with children—were unaware it can be used to pay for qualified K-12 tuition expenses.

“It's concerning to see that in nearly a decade, the number of individuals who do not understand or know what a 529 plan is has increased," said Tim Burke, an Edward Jones principal, in a prepared statement. “What's more alarming is that parents with young children, those who stand to benefit the most from this type of savings plan, are not aware of its many advantages, not just for college, but for K-12 education expenses as well."

The survey found that other priorities outweigh saving for educations. The top three priorities for Americans across generations were preparing for retirement (30 percent), preparing for the unexpected (24 percent) and living in retirement (21 percent). Rounding out the top five were paying for education at 8 percent and planning for their estates or inheritances at 5 percent.

Also, only 8 percent of parents with children said paying for education was a top goal. They ranked preparing for the unexpected as their main financial priority (38 percent).

Eighteen percent of respondents, a slight increase from last year’s pollsters, did indicate that they used the 529 savings plan for education. But 38 percent of Americans said the most common method they used or intended to use for paying for education was personal savings. Scholarships were a close second at 35 percent, followed by federal or state financial aid at 33 percent and private student loans at 20 percent.

Of those who did not or are not planning to save for education using a 529 plan, 71 percent said they were not aware of the features and potential tax benefits, the release noted.

Andersen said Americans leave themselves vulnerable by relying on strategies that aren't necessarily guaranteed, like scholarships, federal or state financial aid. “The numerous tax benefits, investment growth potential and flexibility of a 529 plan make it a valuable investment vehicle for parents saving for their children's future education costs,” he said.