immigration vs metempsychosis

immigration

noun
  • The act of immigrating; the passing or coming into a country of which one is not native born for the purpose of permanent residence. 

  • The process of going through immigration checks at a border checkpoint. 

metempsychosis

noun
  • Transmigration of the soul, especially its reincarnation after death. 

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