enclose vs pen in

enclose

verb
  • to surround with a wall, fence, etc. 

  • to insert into a container, usually an envelope or package 

pen in

verb
  • To enclose (animals) in a pen. 

  • To schedule; fix a date for. 

  • To cause to be stuck in a situation; to be forced into a situation by circumstances. 

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