retrocession vs subsidence

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. 

subsidence

noun
  • The process of becoming less active or severe. 

  • A sinking of something to a lower level, especially of part of the surface of the Earth due to underground excavation, seismic activity or underground or ground water depletion. 

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