memoir vs saga

memoir

noun
  • Any form of narrative describing the personal experiences of a writer. 

  • A biography; a book describing the experiences of a subject from personal knowledge of the subject or from sources with personal knowledge of the subject. 

  • An autobiography; a book describing the personal experiences of an author. 

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 memoir and saga occurred in a corpus of books? (source: Google Ngram Viewer )