I've said this before, but it is interesting how decades in the calendar sense fail to line up with decades in the zeitgeist sense. Like, the '90s actually lasted from 1989 until 2001, and the 2000s were only from 2002 to 2007. The teens went from 2008 to 2016. It remains to be seen how deep into the actual 1920s the '20s will go.
The '60s were 1963-1974. The '70s were 1975-1980. The '80s were 1981-88.
The 40s naturally ran from 1939-1947. The fifties lasted a a whopping 15 years, from 1948-1962