Americans don't appear to be saving all that much money in their 529 college-savings plans.

That’s the upshot of data released Tuesday, which show that the average 529 account has less than $20,000.

As of the end of last year, the average 529 account was $19,584, according to the report by the College Savings Plans Network.

That, of course, is a mere fraction of what it costs to go to college.

Average tuition and fees at four-year private colleges top $30,000, according to the College Board. Total costs are close to $41,000.

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Similar in some ways to 401(k) retirement plans, 529s are state-sponsored programs offering a tax-advantaged way to save for college. Parents typically invest in stock and bond mutual funds with after-tax dollars. Earnings grow free of federal, and generally state, taxes.

Every state offers at least one 529 plan, and parents can invest in any state's plan. Many states give up-front tax deductions for 529 contributions, though California does not.

Many parents are pouring money into 529s as they scramble to keep up with spiraling college costs.

However, the data suggest that many other families aren’t contributing. Only 52% of 529 plans had new contributions in 2013, according to CSPN.

Rising stock prices last year boosted 529 accounts. Total assets nationwide topped $227 billion, up $36 billion from 2012, according to CSPN.

There were 11.6 million accounts last year, up 4.4% from the prior year.

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Follow Walter Hamilton on Twitter @LATwalter