impel vs incite

impel

verb
  • To urge a person; to press on; to incite to action or motion via intrinsic motivation. 

  • To drive forward; to propel an object, to provide an impetus for motion or action. 

incite

verb
  • To stir up or excite; to rouse or goad into action. 

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