concoction vs figment of one's imagination

concoction

noun
  • Something made up, an invention. 

  • A mixture prepared in such a way. 

  • The preparing of a medicine, food or other substance out of many ingredients. 

figment of one's imagination

noun
  • A product of the imagination. 

How often have the words concoction and figment of one's imagination occurred in a corpus of books? (source: Google Ngram Viewer )