execute vs kill by hanging

execute

verb
  • To kill, especially as punishment for a capital crime. 

  • To run, usually successfully. 

  • Coordinate term: murder 

  • To carry out; to put into effect. 

  • To perform. 

  • To carry out, to perform an act; to put into effect or cause to become legally binding or valid (as a contract) by so doing. 

  • To start, launch or run 

kill by hanging

verb
  • to kill someone by suspending them by the neck 

How often have the words execute and kill by hanging occurred in a corpus of books? (source: Google Ngram Viewer )