NEW YORK ( TheStreet) -- Americans nearing and in retirement are seriously underestimating the amount of money they'll need for medical care in their post-working years. While there's a "target figure" attached to health care costs in retirement (more on that in a minute), most health care consumers are off by anywhere from 20% to 30% on their financial estimates for medical services in retirement. According to the Wellness For Life study co-sponsored by Aviva USA and the Mayo Clinic, retirees will need 30% of their annual income for health care costs. But 90% of U.S. retirees think they'll spend less than 20% of their annual income on medical needs, while 70% say they'll spend 10% or less on health care. Philip Hagen, a medical director at the Mayo Clinic, calls that "a significant discrepancy" among for "unrealistic" retirees. Now retirees can at least hang their hat on an actual total price tag for health care costs in retirement -- it's $220,000, according to figures from Fidelity Investments. The Boston mutual fund giant calculates a 65-year-old couple retiring this year will need that $220,000 to cover all medical costs throughout retirement. That doesn't include nursing homes costs, but does include retirees with traditional Medicare coverage. The good news is that the $220,000 figure is 8% less than last year, down from $240,000. The bad news? Only once in the past 10 years -- this year -- has the "total cost" rate declined. In fact, Fidelity says heath care costs for retirees have risen, on average, by 6% each year between 2002 and 2012. There's no question that health care will be at the top of the list of "largest costs" in retirees' late 60s and beyond, Fidelity says. "While lower, this year's estimate is still daunting for many retirees, and it will consume a considerable amount of a couple's retirement savings," says Brad Kimler, executive vice president of Fidelity's benefits consulting division. "It is extremely important that health care costs are factored into retirement savings strategies today so that retirees can be prepared to pay their medical bills throughout retirement." Fidelity notes that the relative decline in total health care costs in retirement may have had a lot to do with the economic downturn that started in 2008. Americans were apparently using less medical services primarily because they couldn't afford them. /p> "Also contributing to the decrease were smaller payment increases to providers (e.g., hospitals, physicians, health plans). Additionally, as baby boomers retire, they bring a large influx of younger enrollees into the Medicare population, reducing the overall average age of participants. Younger retirees tend to have lower health care expenses than older beneficiaries which also contributed to the lower per-enrollee spending," Fidelity says in its health care retiree costs report. Any sustained declines depends largely on the private sector's ability to dig out better "efficiencies" in the U.S. health care system. Consequently, it's an uphill climb for Americans in retirement looking to cover health care costs. But at least now, they have a good idea exactly how much they'll need for those costs. Now it's just a matter of saving up $220,000.