liberate vs unpen

liberate

verb
  • To release from chemical bonds or solutions. 

  • To acquire from an enemy during wartime, used especially of cities, regions, and other population centers. 

  • To release from servitude or unjust rule. 

  • To release from slavery: to manumit. 

  • To release from restraint or inhibition. 

  • To acquire from another by theft or force: to steal, to rob. 

unpen

verb
  • To release from a pen. 

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