bowler hat vs fedora

bowler hat

noun
  • A hard round black felt hat with a narrow brim, formerly worn by men. 

verb
  • Synonym of bowler hat out (“eject someone from an organization”) 

fedora

noun
  • A felt hat with a fairly low, creased crown with a brim that can be turned up or down. 

How often have the words bowler hat and fedora occurred in a corpus of books? (source: Google Ngram Viewer )