The survey also said 8 percent of U.S. residents born from 1946-64 have taken their parents into their homes for health or financial reasons.

Thirty-seven percent of those surveyed not supporting a parent admitted they expect to, while about half said they worry about being able to provide such care.

Most of the people polled who do so describe the experience as a "minor sacrifice" or "no sacrifice at all," USA Today said.

An AARP study showed about 34 million people in the United States spend about 21 hours a week serving as unpaid caregivers for other adults.

The average unpaid caregiver is a 46-year-old woman who also works outside the home but has to cut back on her hours to fulfill her familial obligations, the newspaper said.

AARP estimated the economic impact of this care last year was about $350 billion -- more than the U.S. government spent on Medicare in 2005, USA Today reported in Monday's editions.