infrahuman vs superhuman

infrahuman

noun
  • A creature that is not (yet) at the level of understanding of a human being, such as a presymbolic child or an animal. 

adj
  • Below the level of the human. 

superhuman

noun
  • A human being with remarkable abilities or superpowers. 

adj
  • Beyond what is possible for a human being. 

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