exert vs implement

exert

verb
  • To put in vigorous action. 

  • To make use of, to apply, especially of something non-material. 

implement

verb
  • To bring about; to put into practice; to carry out. 

noun
  • A tool or instrument for working with. 

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