carceral vs penal

carceral

adj
  • Of or pertaining to imprisonment or a prison. 

penal

adj
  • Of or relating to punishment. 

  • Exorbitant. 

  • Serving as a place of punishment. 

  • Subject to punishment; punishable. 

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