armed robbery vs filch

armed robbery

noun
  • An theft where the thieves are carrying weapons. 

filch

noun
  • An act of filching; larceny, theft. 

  • Something which has been filched or stolen. 

verb
  • To illegally take possession of (something, especially items of low value); to pilfer, to steal. 

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