Rebel vs doughboy

Rebel

noun
  • A Confederate soldier; of the Confederate States of America; of the American Civil War. 

doughboy

noun
  • An American infantryman, especially one from World War I. 

  • A kind of flour dumpling. 

  • Frybread. 

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