make a difference vs propel

make a difference

verb
  • To carry out an action, the result of which is a significant change, or an altered circumstance. 

  • To be of importance; to matter. 

propel

verb
  • To provide an impetus for non-physical change, to make to arrive to a certain situation or result. 

  • To provide an impetus for motion or physical action, to cause to move in a certain direction; to drive forward. 

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