fairy tale vs shaggy-dog story

fairy tale

noun
  • A delightful and ideal situation of a kind attained by very few. 

  • A story presented as true that is not believable. 

  • A folktale featuring fairies or similar fantasy characters. 

shaggy-dog story

How often have the words fairy tale and shaggy-dog story occurred in a corpus of books? (source: Google Ngram Viewer )