burgomaster vs commissioner

burgomaster

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

commissioner

noun
  • An official in charge of a government department, especially a police force. 

  • Someone commissioned to perform certain duties. 

  • A member of a commission. 

  • Someone who commissions something. 

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