obeah vs voodoo

obeah

verb
  • To bewitch using this kind of folk magic. 

noun
  • A magician or witch doctor of the magic craft. 

  • A spell performed in the practice of the magic craft; an item associated with such a spell. 

  • A form of folk magic, medicine or witchcraft originating in Africa and practised in parts of the Caribbean. 

voodoo

verb
  • To bewitch someone or something using voodoo 

noun
  • Any of a group of related religious practices found chiefly in and around the Caribbean, particularly in Haiti and Louisiana. 

  • The spiritual beliefs of the Ewe/Fon of West Africa, practiced chiefly in Benin and in the south of Togo. 

  • Any sort of magical or irrational approach to a problem. 

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