excavator vs navvy

excavator

noun
  • A person who excavates. 

  • A vehicle, often on tracks, used to dig ditches etc. 

  • A curette used to scrape out pathological material. 

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. 

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