depreciation vs retrocession

depreciation

noun
  • The state of being depreciated; disparagement. 

  • The decline in value of assets. 

  • The measurement of the decline in value of assets. Not to be confused with impairment, which is the measurement of the unplanned, extraordinary decline in value of assets. 

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. 

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