clientage vs purchasing

clientage

noun
  • the condition of being a client 

  • clients collectively; clientele 

purchasing

noun
  • An act or process of making a purchase. 

  • A part of an organization that manages such processes 

  • A complex, organized process in large organizations for obtaining goods that may include identification of requirements, approvals, supplier management, negotiation, receipt of goods, and payment. 

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