crusader vs warfighter

crusader

noun
  • An American, especially a soldier or leader who wages war against Islamist militants. 

  • the crusaders of the Middle Ages 

  • A Westerner; a Christian, especially of European descent or a missionary. 

  • A fighter in the medieval Crusades who had taken the Cross. 

  • A person engaged in a crusade. 

  • (either attributively or in the plural) The United States and its Western allies. 

warfighter

noun
  • A soldier (especially of the United States military). 

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