electrocute vs string up

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. 

string up

verb
  • To kill (a person) by hanging, especially to lynch. 

  • To concatenate; to link in a line. 

  • To suspend by means of rope, cord or similar material. 

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