adulterate vs pejorate

adulterate

verb
  • To corrupt, to debase (someone or something). 

  • To make less valuable or spoil (something) by adding impurities or other substances. 

pejorate

verb
  • To make or become worse; to deteriorate or to worsen. 

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