pickpocket vs pilfer

pickpocket

verb
  • To pick pockets; to steal. 

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

pilfer

verb
  • To steal in small quantities, or articles of small value; to practise petty theft. 

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