2001 was the first year the Census Bureau's Survey of Income and Program Participation asked the question “Are you a grandparent?” of respondents who were at least 30 years old and who had a child at least 15 years old. Back then there were 56.1 million grandparents. In 2014, the number had increased by one-quarter to 69.5 million.
Along with the increase in the number of grandparents, the percent of adults age 30 or older with a child at least age 15 who are grandparents has significantly increased. Being a grandparent for those adults is now the norm - 61% of women and 57% of men with those qualifications are grandparents.
Of all adults age 30 and older, 37% were grandparents in 2014.
When targeting families for community leisure venues, including FECs, don't forget the grandparents. They have a definite tendency to splurge on their grandchildren.