assuage vs unburden

assuage

verb
  • To lessen the intensity of, to mitigate or relieve (hunger, emotion, pain etc.). 

  • To pacify or soothe (someone). 

unburden

verb
  • To free from burden, or relieve from trouble. 

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