depreciate vs escalate

depreciate

verb
  • To lessen in price or estimated value; to lower the worth of. 

  • To decline in value over time. 

  • To belittle or disparage. 

escalate

verb
  • To climb. 

  • To increase (something) in extent or intensity; to intensify or step up. 

  • In technical support, to transfer a customer, a problem, etc. to the next higher level of authority 

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