The 'decade' of the 1920s runs from January 1, 1920 to December 31, 1929.
There have been a lot of changes during/in/over the past two 'decades'.
a 'decade' of drought [=a drought that lasted 10 years]
(..) This is a very, very good brownie. l'm gonna fight for it. l've been on a diet every day since l was , which basically means l've been hungry for a decade. l've had a series of not-nice boyfriends, one of whom hit me. Uh, and every time l get my heart broken, the newspapers splash it about (..)1999 Notting Hill