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]
(..) You all right. These aren't even on the shelf yet. Here. Check it out. -Look at that. Look at that. -Look at that. It's snowing. Ten years old, huh? A decade. Double digits. The big -. You don't like it? -No, no, it's great. -You hate it. I should've gotten you (..)2005 Madagascar