I haven't read the full study, but did they adjust for the overall population distribution?

One would expect a tapering right tail on the simple basis that there aren't many people alive to be nostalgic about their 70s.

Without that kind of adjustment (i'm not sure how you'd do it), it's hard to read much from these graphical shapes.

I think it'd be a lot simpler to do a table like this:

Yes, I'm being that guy