cunning folk vs witch doctor

cunning folk

noun
  • professional or semi-professional practitioners of magic (who were often charlatans) who were active from at least the 15th up until the early 20th century. 

witch doctor

noun
  • A person (often male) who is believed to ward off witchcraft and heal through magical powers; a shaman. 

How often have the words cunning folk and witch doctor occurred in a corpus of books? (source: Google Ngram Viewer )