backstab vs stitch up

backstab

verb
  • to attack someone (especially verbally) unfairly in a deceitful, underhand, or treacherous manner, especially when they're not present in the place or situation that it happens. (as if stabbing them in the back). See backbite. 

stitch up

verb
  • To maliciously or dishonestly incriminate someone; to set up (in the sense trap or ensnare) 

  • To join or close by sewing. 

  • To prank, trick, or deceive (a person), whether or not malice is intended. 

  • To fabricate (e.g. a legal case). 

  • To complete arrangements for (a situation), especially clandestinely or prematurely and for one's own benefit. 

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