occultism vs voodooism

occultism

noun
  • The study of the supernatural 

  • A belief in occult powers and the hope of controlling them 

voodooism

noun
  • Any voodoo practice. 

  • A religious cult, from Haiti, involving witchcraft and sorcery. 

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