retrocession vs retrogress

retrocession

noun
  • The act of retroceding; a going back. 

  • The transfer of risk from one reinsurer to another. 

  • The return of land, rights, etc. previously ceded. 

  • Metastasis of an eruption or tumour from the surface to the interior of the body. 

retrogress

noun
  • A retrogression. 

verb
  • To return to an earlier, simpler or worse condition; to regress. 

  • To go backwards; to retreat. 

  • To return to bad behaviour; to relapse. 

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