prove out vs shake down

prove out

verb
  • To demonstrate the feasibility of; to show or be shown to be feasible, accurate, true, satisfactory, as expected, hoped, stated, etc. 

  • To turn out to be feasible, accurate, true, satisfactory, as expected, hoped, stated, etc. 

shake down

verb
  • To subject something to a shakedown test. 

  • To shake someone so money falls from their pockets. 

  • To cause something to fall down by shaking it, or something it is attached to. 

  • To extort money from (someone) by means of threats. 

  • To search exhaustively. 

How often have the words prove out and shake down occurred in a corpus of books? (source: Google Ngram Viewer )