commando vs guerrilla warfare

commando

noun
  • A small fighting force specially trained for making quick destructive raids against enemy-held areas. 

  • A commando trooper. 

  • An organized force of Boer troops in South Africa; a raid by such troops. 

guerrilla warfare

noun
  • Combat using groups of irregular, light, mobile troops within areas occupied by an enemy force, usually through hit-and-run tactics. 

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