discourage vs prevent

discourage

verb
  • To persuade somebody not to do (something). 

  • To extinguish the courage of; to dishearten; to depress the spirits of; to deprive of confidence; to deject. 

noun
  • Lack of courage 

prevent

verb
  • To stop (an outcome); to keep from (doing something). 

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