contract killing vs decapitation

contract killing

noun
  • The act of hiring or procuring a contract killer. 

decapitation

noun
  • Beheading; the act of beheading or decapitating. 

  • The ousting or destruction of the ruling body of a government or other organization. 

  • The unseating of a senior politician. 

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