epitome vs poster child

epitome

noun
  • A representative example. 

  • The embodiment or encapsulation of a class of items. 

  • A brief summary of a text. 

  • The height; the best; the most vivid. 

poster child

noun
  • One who is a prototypical or quintessential example of something. 

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