Bushman vs autochthon

Bushman

noun
  • A person who lives in the bush, especially a member of a community or ethnic group who lives in the bush. 

  • A member of one of the foraging ethnic groups native to southwestern Africa, mostly the Kalahari. 

autochthon

noun
  • A large mass of rock in the place of its original formation, rooted to its basement (foundation rock) as opposed to an allochthon or nappe which has shifted from the place of formation; an autochthonous rock formation. 

  • The earliest inhabitant of an area; an aborigine. 

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