drawing card vs stool pigeon

drawing card

noun
  • Synonym of drawcard (“something that attracts patronage to a place or an event”) 

stool pigeon

noun
  • An informer to the authorities, especially one who gives up criminal associates. 

  • A pigeon tied to a stool by a piece of twine, used as a decoy to entice free-flying birds to the ground to be shot or trapped. 

How often have the words drawing card and stool pigeon occurred in a corpus of books? (source: Google Ngram Viewer )