Swan vs mettle

Swan

noun
  • someone connected with Swansea City Football Club, as a fan, player, coach, etc. 

  • someone connected with the Sydney Swans, as a fan, player, coach, etc. 

name
  • A surname transferred from the nickname. 

mettle

noun
  • Good temperament and character. 

  • A quality of endurance and courage. 

adj
  • Spirited, vigorous, stout-hearted. 

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