degrade vs deteriorate

degrade

verb
  • To lower in value or social position. 

  • To reduce in altitude or magnitude, as hills and mountains; to wear down. 

  • To reduce in quality or purity. 

deteriorate

verb
  • To make worse; to make inferior in quality or value; to impair. 

  • To grow worse; to be impaired in quality; to degenerate. 

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