Colonel vs centurion

Colonel

noun
  • The military officer title. 

centurion

noun
  • An officer of the ancient Roman army, in command of a century of soldiers. 

  • A player who scores a century. 

  • A pilot in the United States Navy who has performed 100 night landings on an aircraft carrier. 

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