Few U.S. residents have any idea how much they will be spending on health care after they retire.

Analysts at First Command Financial Services Inc., Fort Worth, Texas, come to that conclusion in a summary of results from a survey of 1,000 U.S. consumers ages 25 to 70 with annual household incomes of at least $50,000.

About 72% of the survey participants said they are at least somewhat concerned about health care costs in retirement, but the participants estimated they would need an average of just $33,000 above traditional retirement savings to cover those post-retirement health care costs.

Experts now estimate an individual who retires today and lives to age 100 will need an average of about $166,000 for out-of-pocket expenses, First Command analysts estimate.

Only about a third of the participants said they made an effort to include health care costs in retirement planning, the analysts report.

Non-retired participants with a written financial plan were about twice as likely as other non-retired participants to say they are taking post-retirement health care costs into consideration, the analysts write.