hawker vs travelling salesman

hawker

noun
  • A peddler, a huckster, a person who sells easily transportable goods. 

  • Any dragonfly of the family Aeshnidae; a darner. 

  • Someone who breeds and trains hawks and other falcons; a falconer. 

travelling salesman

noun
  • A man who travels, often within a certain territory, soliciting orders or selling goods. 

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