buyer vs shop assistant

buyer

noun
  • A person who purchases items for resale in a retail establishment. 

  • A person who purchases items consumed or used as components in the manufacture of products. 

  • A person who makes one or more purchases. 

shop assistant

noun
  • An employee in a shop, a shopkeeper. 

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