lascar vs navigator

lascar

noun
  • A sailor from India or Southeast Asia, especially as serving on a European ship. 

  • Any of various nymphalid butterflies of the Asian genera Pantoporia and Lasippa. 

  • A tent-pitcher; also a type of artilleryman. 

navigator

noun
  • A sea explorer. 

  • A device that navigates an aircraft, automobile or missile. 

  • A person who navigates, especially an officer with that responsibility on a ship or an aircrew member with that responsibility on an aircraft. 

  • A user interface that allows navigating through a structure of any kind. 

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