We are a nation of illiterates. Financial illiterates, that is.

Despite a proliferation of games and apps, and efforts by many schools to teach the subject, financial literacy declined between 2009 and 2012, according to a survey.

(Read More: Financial Literacy Games: Tools or Toys?)

"Directionally, it was discouraging," said Gerri Walsh, president of the Investor Education Foundation at the Financial Industry Regulatory Authority, which conducted the survey. "We haven't seen great improvement, and that's where we want to go."

The foundation asked a series of questions about respondents' financial habits, and gave them a quiz to measure their capability. A majority of respondents, 61 percent, were unable to answer three of the five questions correctly. In 2009, that number was just 58 percent.

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The results come as teens and young adults are being asked to make increasingly momentous decisions, such as taking out loans for college and managing credit card debt.

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(See More: The Young & the Jobless)

"We see that 26 percent of Americans have some form of medical debt, and 20 percent have student loans," Walsh said. "Overall, the respondents to our survey said they were very concerned about debt."

That concern can translate into reluctance to spend—a prudent move for individuals but problematic for an economy struggling to gain momentum.

"In my view, the student debt market, the fact that young people are now facing these challenges, is a very compelling reason to have financial education in schools," said Annamaria Lusardi, a professor of economics and accountancy at George Washington University's business school.

Not surprisingly, the survey found that younger people, as well as those earning less than $25,000 or lacking a college educations (in short, those most vulnerable to mistakes such carrying too much credit card debt) were less financially literate than wealthier, better educated respondents.

Another troubling trend, Walsh says, is an increase in alternative lending, including payday and auto title loans. Some 30 percent of respondents in the most recent poll made use of these high-cost credit options, while in the 2009 survey, just 23 percent had used them in the previous five years.

(Read More: Payday Loans Cost Economy $1 Billion in 2011: Study)

The data had some bright spots, Walsh said. The proportion of people who said they are having an easier time making ends meet was 40 percent in 2012, versus 36 percent in 2009.

If the video games, apps and instruction have failed to boost financial literacy, what can be done?

"We need to keep on banging the drum, experimenting with ways to communicate with more audiences," Walsh said.

Speaking of communication, "If the disclosures about financial services and products that consumers are considering are dense, and not in plain language, we are asking too much," she added.

It may also make sense to reframe some financial choices. For example, Walsh said, when people start a job, perhaps they should be signed up to participate in a company retirement plan unless they opt out—the opposite of current practices.

The bottom line, she said, is that "we need to make sure that we're engaging in financial education cradle to grave so that people have the skills they need."