abstruseness vs esotericism

abstruseness

noun
  • The property of being abstruse; abstrusity. 

esotericism

noun
  • The tendency to promote or desire the esoteric. 

  • Doctrines or practices of esoteric knowledge. 

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