depreciation vs lowering in value

depreciation

noun

  • The decline in value of assets. 

  • The state of being depreciated; disparagement. 

  • 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. 

lowering in value

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