12 vs boy in blue

12

noun

  • Collectively, police or law enforcement. 

  • See also: fuck 12 

symbol

  • Used by fans of American football, positioning themselves as the 12th member of an 11-player team. 

boy in blue

noun

  • A policeman. 

How often have the words 12 and boy in blue occurred in a corpus of books? (source: Google Ngram Viewer )