armed robbery vs heist

armed robbery

noun
  • An theft where the thieves are carrying weapons. 

heist

noun
  • A robbery or burglary, especially from an institution such as a bank or museum. 

  • A fiction genre in which a heist is central to the plot; a work in such a genre. 

verb
  • To steal, rob, or hold up (something). 

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