[acheron]

Everyone needs to stop this hypercorrection nonsense. That only applies to centuries and millennia because they're ordinal numbers. You say "20th century" and "21st century". But you say "1990s" and "2020s". Unless you start saying "201st decade" you are wrong.

Also, nobody ever complained about decades until just this year, because it's obviously wrong. I don't even remember it in 2010. I think it's a bunch of kids who vaguely remember the 21st century starting in 2001 (which is correct, of course) but never realized the reason, and are having hypercorrection issues now that they're older.