doughboy vs ground pounder

doughboy

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

  • A kind of flour dumpling. 

  • Frybread. 

ground pounder

noun
  • A military soldier whose primary role is infantry or the use of ground-based materiel. 

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