folktale vs saga

folktale

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

saga

noun
  • Something with the qualities of such a saga; an epic, a long story. 

  • An Old Norse (Icelandic) prose narrative, especially one dealing with family or social histories and legends. 

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