buyer vs customer base

buyer

noun
  • A person who makes one or more purchases. 

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

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

customer base

noun
  • A group of customers and/or consumers that a business serves. 

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