Age-Heaping

You never know where you are going to find an interesting idea. From the National Endowment of the Arts' report, Age and Arts Participation is this fascinating nugget which makes sense but which I never really considered.

A century ago, many Americans did not know exactly how old they were, so they often would round off their age to the nearest five years, a phenomenon that demographers call “age-heaping.” As late as 1910, for example, the U.S. Census listed 24 percent more 20-year-olds than 19-year-olds.