electrocute vs send to the gas chamber

electrocute

verb
  • To kill by electric shock. 

  • To execute by electric shock, often by means of an electric chair. 

  • To inflict a severe electric shock (not necessarily fatal) upon. 

send to the gas chamber

How often have the words electrocute and send to the gas chamber occurred in a corpus of books? (source: Google Ngram Viewer )