HORSE vs stud poker

HORSE

noun
  • A poker variant consisting of five different poker variants, with the rules changing from one variant to the next after every hand. 

stud poker

noun
  • Any of several versions of poker in which some cards are dealt face-down and some face-up. 

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