let loose vs set free

let loose

verb
  • To free; to release from restraint. 

  • To break wind. 

  • To shout, make a loud sound, or perform a sudden, vehement action; to behave in a raucous, frenzied manner. 

set free

verb
  • To release, to free, to give freedom to. 

How often have the words let loose and set free occurred in a corpus of books? (source: Google Ngram Viewer )