Most U.S. adults think long term care is much cheaper than it is, and they expect Medicare to cover a far larger share of the LTC tab than it actually does.

About 80% of U.S. adults seem to understand that the average chance of an individual age 65 or older needing long term care is more than 40%, but 70% said they think the average cost of nursing home care is $30,000 per year, according to researchers at John Hancock Life Insurance Company, Boston, a unit of Manulife Financial Corp., Toronto.

The actual national average cost is about $70,000 per year, the researchers report.

Similarly, about 40% of survey participants said they think Medicare covers the cost of nursing home care for people with Alzheimer’s disease.

Medicare does not cover the cost of nursing home care for people with Alzheimer’s disease, the Hancock researchers note.

The researchers drew the statistics from results from a recent survey of 959 U.S. residents ages 21 to 75.

Hancock commissioned the survey to support a private LTC insurance consumer education campaign.

“Long term care can be a very, very tough thing to think about,” said Laura Moore, president of John Hancock Long Term Care, today at a press conference in Washington. “It’s more comfortable not to think about it, and, unfortunately, that’s what most consumers are doing.”

Medicare and Medicaid “do help many, but most of us should realize that we ourselves will most probably have to pay for the long term care services we may need,” Moore said.

Millions of baby boomers are caring for their parents or other relatives, but a declining birth rate means that, when the boomers themselves are older, “many who need care will not have children to fall back on,” said Mathew Greenwald, a Washington-based senior issues analyst.