GI vs ground pounder

GI

noun
  • A member of the U.S. military. 

  • One who is demanding and strict, in the manner of a stereotypical member of the military. 

verb
  • To clean aggressively. 

ground pounder

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

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