endangered vs familiar

endangered

adj
  • in danger, at risk, said of something where there is a strong possibility something bad will happen to it (for example, a species in danger of going extinct) 

familiar

adj
  • Of or pertaining to a family; familial. 

  • Known to one, or generally known; commonplace. 

  • Intimate or friendly. 

  • Acquainted. 

noun
  • An attendant spirit, often in animal or demon form. 

  • The officer of the Inquisition who arrested suspected people. 

  • A member of a pope's or bishop's household. 

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