matey vs shellback

matey

noun
  • A fellow sailor; often used affectedly, especially when portraying a pirate. 

  • A dockyard worker. 

adj
  • Sociable or friendly. 

shellback

noun
  • A worldly sailor. 

  • A sailor who has crossed the equator. 

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