counteract vs prevent

counteract

verb
  • To deliberately act in opposition to, to thwart or frustrate 

  • To have a contrary or opposing effect or force on 

noun
  • An action performed in opposition to another action. 

prevent

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

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