internecine vs war-ridden

internecine

adj
  • Mutually destructive; most often applied to warfare. 

  • Characterized by struggle within a group, usually applied to an ethnic or familial relationship. 

war-ridden

adj
  • Dominated or plagued by war. 

How often have the words internecine and war-ridden occurred in a corpus of books? (source: Google Ngram Viewer )