pickpocket vs skyjacker

pickpocket

noun
  • One who steals from the pocket of a passerby, usually by sleight of hand. 

verb
  • To pick pockets; to steal. 

skyjacker

noun
  • A person who commits skyjacking, who skyjacks. 

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