let go vs put to work

let go

verb
  • To dismiss from employment. 

  • To release from one's grasp; to go from a state of holding on to a state of no longer holding on. 

  • To ignore (a comment, etc.). 

  • To emotionally disengage or to distract oneself from a situation. 

  • To fail to maintain a standard of appearance, behavior, or performance. 

  • Used other than figuratively or idiomatically: see let, go. 

  • To gain weight 

put to work

verb
  • Give a job; Force to work (even if it is make-work) 

  • to put to use 

How often have the words let go and put to work occurred in a corpus of books? (source: Google Ngram Viewer )