apologue vs folktale

apologue

noun
  • A short story with a moral, often involving talking animals or objects; a fable. 

  • The use of fable to persuade the audience. 

folktale

noun
  • A tale or story that is part of the oral tradition of a people or a place. 

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