burgomaster vs prepositus

burgomaster

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

prepositus

noun
  • The presiding officer of various civil bodies. 

  • A provost: the presiding officer of various ecclesiastical bodies. 

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