bobby vs burgomaster

bobby

noun
  • A police officer. 

  • A banana that is extra small in size. 

  • A penis. 

  • A railway signaller. 

  • A calf that is slaughtered in its first month, usually because it has no mother or because it is undersized or otherwise defective. 

  • Cocaine. 

burgomaster

noun
  • The mayor, or head magistrate, of a town in the Netherlands, Belgium, Germany and certain other countries. 

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