Grandparents represent a bigger chunk of the population than ever before, according to new data from the Census Bureau.

The number of grandparents in the United States rose to 69.5 million in 2014, up from 65.1 million in 2009, the bureau reported last week. The youngest baby boomers turned 50 in 2014, and the country’s 75.4 million boomers make up an exceptionally large pool of potential grandparents.