In what sense is 'one in 100 year' equivalent to '0.2% every year'? With the latter you'd expect 0.2 of them in 100 years?

(Totally agree the phrasing is misleading to the layman though, which is really the only reason for it to exist anyway, in an attempt to be more relatable.)

Not likely. The 60’s had riots, Vietnam, political assassinations, Cuban missile crisis and ongoing Cold War MAD fears. The 1910-1940’s were jam packed with world wars, the Great Depression, Spanish flu, and more. And before that a quarter of all children died young. Every generation ever. What’s actually unprecedented is having a few years between crises where things are actually pretty ok!

That's the beauty (?) of statistics for you!

Probably 9/11. The resulting wars in Afghanistan and Iraq were largely fought by Millennials (with some gen-z nearer to the end, I think—but the initial invasions heavily involved "elder millennials" [EDIT: and x/y "cuspers", especially for Afghanistan], with younger millennials involved in the long middle period). Though Vietnam (among other wars, but it seems most-comparable) was easily within living memory at the time, so I'm not so sure about "once in a lifetime" for the wars. That kind of wildly-successful attack on the US, though—that part might more-or-less qualify.

Millennial bingo:

  2008 financial crisis

  2020 pandemic (& Brexit)

  2022 war start + highest winter temperatures ever recorded 

  2023 economic downturn and layoffs

Who knows what the future holds.

maybe 9/11 + Iraq war, not sure... losing count at this point