(AP) — After years of increases, testing for colon cancer may be leveling off.

A large government survey of older adults last year found about two-thirds had gotten the recommended screening. That’s the same level as 2010, and the first year in a decade of no increase.

Last year’s survey included cellphones for the first time, which may have affected results. But other research has suggested the increase in screening is slowing down. Health officials say it’s not clear why.

The Centers for Disease Control and Prevention released the report Tuesday. It’s based on a national telephone survey of more than 200,000 adults ages 50 to 75.