autonym vs xenonym

autonym

noun
  • A name used by a group or category of people to refer to themselves or their language, as opposed to a name given to them by other groups. 

  • An infraspecific name in which the specific epithet is repeated. 

  • A work published under the author's true name. 

  • The true name of a person or other entity, especially an author. 

xenonym

noun
  • A name for a people or a language or a city etc. which is not used by the natives themselves. Germans, for example, is a xenonym for people who call themselves Deutsche, Cologne a xenonym for Köln, Austria for Österreich etc. 

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