Most workers have an age in mind for when they would be willing to call it quits.

But the traditional retirement age — 65 — could be changing.

Research by Transamerica Center for Retirement Studies and the Aegon Center for Longevity and Retirement looked at what age workers around the world expect to retire from all-paid employment.

While the median (the middle in a list of numbers) age in the U.S. was 66, other countries varied. The Netherlands came in with the highest age, 67. China and Turkey came in with the lowest at 58.

The median was 65.

The retirement age is creeping higher in the U.S. and elsewhere, said Catherine Collinson, CEO and president of the Transamerica Center for Retirement Studies.

In the U.S., according to the Social Security Administration, full retirement age for individuals born in 1960 and later is 67.

Other countries are also moving in that direction, Collinson said. The Netherlands is already at 67, while France, Spain and Poland all have plans to move towards that age.

"That tends to be the prevailing benchmark," Collinson said.