extirpate vs improve

extirpate

verb
  • To pull up by the roots; uproot. 

  • To destroy completely; to annihilate, to cause to go extinct locally. 

  • To surgically remove. 

improve

verb
  • To make (something) better; to increase the value or productivity (of something). 

  • To become better. 

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