Untermensch vs übermensch

Untermensch

noun
  • An inferior person; a subhuman, especially in a Nazi racial hierarchy. 

übermensch

noun
  • An overman (“higher” man) who has overcome (transcended) his (mere) humanity. (There is no consensus regarding the exact nature of the figure of the übermensch in Nietzsche’s philosophy.) 

  • A member of the proposed Aryan super race. 

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