compel vs enslave

compel

verb
  • To overpower; to subdue. 

  • To force, constrain or coerce. 

  • To exact, extort, (make) produce by force. 

enslave

verb
  • To make subservient; to strip one of freedom; enthrall. 

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