bowler vs fireman

bowler

noun
  • The pitcher. 

  • A bowler hat; a round black hat formerly popular among British businessmen. 

  • One who engages in the sport of bowling. 

  • A player selected mainly for his bowling ability. 

  • The player currently bowling. 

fireman

noun
  • A relief pitcher (reflecting the figurative analogy of rescuing the situation). 

  • A safety inspector in coal mines. 

  • An assistant on any locomotive, whether steam-powered or not. 

  • Someone (especially one who is male) who is skilled in the work of fighting fire. 

  • A person (originally a man) who keeps the fire going underneath a steam boiler (originally, shoveling coal by hand), particularly on a railroad locomotive or steamship. 

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