purser vs registrar

purser

noun
  • The person responsible for handling the accounts on a ship, or for dealing with the passengers on a ship or aircraft. 

registrar

noun
  • The person responsible for record-keeping related to a museum's or archive's collection. 

  • An officer in a university who keeps enrollment and academic achievement records. 

  • a service that manages domain names. 

  • A doctor receiving advanced specialist training in some countries in order to become a consultant. 

  • The chief executive officer of a judicial forum, in charge of the entire registry of the department. 

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