duress vs vampirism

duress

noun
  • Constraint by threat. 

  • Restraint in which a person is influenced, whether by lawful or unlawful forceful compulsion of their liberty by monition or implementation of physical enforcement; legally for the incurring of civil liability, of a citizen's arrest, or of subrogation, or illegally for the committing of an offense, of forcing a contract, or of using threats. 

verb
  • To put under duress; to pressure. 

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 duress and vampirism occurred in a corpus of books? (source: Google Ngram Viewer )