cattle call vs showdown

cattle call

noun
  • An audition which is open to the public and thus draws a large number of applicants, many of whom are inexperienced. 

showdown

noun
  • The final battle between two nemeses, in which there can be but one victor. 

  • The final round in a poker match, where the all remaining players' cards have to be put down on the table and shown. 

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