do away with vs string up

do away with

verb
  • To have someone killed. 

  • To abolish; to put an end to; to eliminate. 

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 do away with and string up occurred in a corpus of books? (source: Google Ngram Viewer )