Swan vs kingpin

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. 

kingpin

noun
  • The axis around which steered wheels pivot; a bolt that holds the axis in place—a kingbolt. 

  • The bolt holding together the truck of a roller skate or skateboard. 

  • The pivot or connector between a tractor and trailer in the fifth-wheel coupling of semi-trailer truck. 

  • The pin at the centre of the triangle of bowling pins (originally the tallest pin in kayles). Sometimes also the headpin at the apex. 

  • The most important person in an undertaking or organization. 

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