Usage patterns
〈数〉年間for ... years
He lived in America for three years.
〈時〉年間during the ... era
Many castles were built during the Kan'ei era.
年間を通じてthroughout the year
This region is mild throughout the year.
〈数〉年間で〈数〉within a span of ... years, (something happens)
The population doubled over a span of five years.