SOS vs buzzer

SOS

noun
  • A children's game in which players take turns to place S's and O's on a grid, collecting points by creating an "SOS" sequence. 

  • The conventional Morse code call made by a ship in distress. 

buzzer

noun
  • One who, or that which, buzzes; an insect that buzzes. 

  • A device that makes a buzzing sound. 

  • A run scored from an overthrow. 

  • A police badge. 

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