navvy vs peon

navvy

noun
  • A laborer on a civil engineering project such as a canal or railroad. 

verb
  • To carry out physical labor on a civil engineering project. 

peon

noun
  • A lowly person; a peasant or serf; a labourer who is obliged to do menial work. 

  • A person of low rank or importance. 

  • A messenger, foot soldier, or native policeman. 

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