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]
(..) about what it would be like if she did. Oh, good, you're all here. I've decided that if the three of you drop whatever you're working on and join me... ...we could lick cold fusion in less than a decade, years tops. Go away? Hmm. Could it be me? Hey, guys, what's up? (..)2008 TvShow: The Big Bang Theory Title: The Jerusalem Duality Season: 1 Episode 12