customer vs trafficker

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. 

trafficker

noun
  • Someone who traffics; a trader or merchant. 

  • A human trafficker or drug trafficker. 

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