immigrant vs transmigration

immigrant

noun
  • A non-native person who comes to a country from another country to permanently settle there. 

  • A plant or animal that establishes itself in an area where it previously did not exist. 

adj
  • Of or relating to immigrants or the act of immigrating. 

transmigration

noun
  • Departure from one's homeland to live in another country; migration. 

  • The movement of a soul from one body to another after death; metempsychosis. 

  • A change from one state of existence to another. 

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