four of a kind vs stoker

four of a kind

noun
  • Four cards of the same rank. 

stoker

noun
  • A device for stoking a fire; a poker. 

  • A person who stokes, especially one on a steamship or steam train, who stokes coal in the boilers. 

  • A person who pedals on the back of a tandem bicycle. 

  • A device that feeds coal into a furnace, etc., automatically. 

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