certificate(s) vs memoir

certificate(s)

memoir

noun
  • 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. 

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

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

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