let out vs pack in

let out

verb
  • To rent out. 

  • Of a school: to finish for the day or term, allowing the pupils to go home. 

  • To disclose. 

  • Of sound, to emit. 

  • To allow to operate at higher speed by adjusting controls. 

  • To release. 

  • To enlarge by adjusting one or more seams. 

pack in

verb
  • To transport to base camp, especially by backpack. 

  • To include (especially of a large amount). 

  • To give up, to quit. 

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