nightstick vs swatter

nightstick

noun
  • A long narrow pole-like club carried by police and security personnel, for use in self-defense. 

swatter

verb
  • To spill water about. 

noun
  • Something used to swat with; a flyswatter. 

  • Someone who swats. 

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