ground pounder vs pongo

ground pounder

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

pongo

noun
  • A soldier. 

  • A lazy, good for nothing person. 

  • A canyon or gorge in South America especially cutting through a ridge or mountain range. 

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