Kardecism vs spiritism

Kardecism

noun
  • A type of spiritualism (defined broadly as the belief that the dead communicate with the living, especially through a medium) whose followers believe in Allan Kardec's Spiritist Codification, a series of five books containing moral and other teachings. 

spiritism

noun
  • Spiritualism 

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