purchasing vs unloading

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. 

unloading

noun
  • The act by which something is unloaded. 

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