commando vs leatherneck

commando

noun
  • A commando trooper. 

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

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

leatherneck

noun
  • A soldier. 

  • Specifically, a marine. 

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