expedite vs prepone

expedite

verb
  • To perform (a task) fast and efficiently. 

  • To accelerate the progress of. 

  • To perform the duties of an expediter. 

adj
  • Expeditious; quick; prompt. 

  • Free of impediment; unimpeded. 

prepone

verb
  • To reschedule to a time earlier than the current scheduled time. 

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