That is a decent control, though I think that finding "all people born in 1900" is probably more difficult than you'd imagine. I propose adding "who died 20-30

That is a decent control, though I think that finding "all people born in 1900" is probably more difficult than you'd imagine. I propose adding "who died 20-30 years ago" because that will make it easier to find comprehensive data. You would need to make sure your survey isn't biased towards people who were notable enough at age 90 to be included, because living past 100 makes people notable in a different way.