customer vs hawker

customer

noun
  • A patron, a client; one who purchases or receives a product or service from a business or merchant, or intends to do so. 

  • A native official who exacted customs duties. 

  • A person, especially one engaging in some sort of interaction with others. 

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. 

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