oppression vs vampirism

oppression

noun
  • The exercise of authority or power in a burdensome, cruel, or unjust manner. 

  • The act of oppressing, or the state of being oppressed. 

  • A feeling of being oppressed. 

vampirism

noun
  • extortion 

  • practices associated with vampires, in particular blood-drinking and the draining of a victim's life-force. 

  • Systemic lupus erythematosus (autoimmune disease) 

  • the state of being a vampire 

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