disburden vs weigh down

disburden

verb
  • To free from a source of mental trouble. 

  • To rid of a burden; to free from a load carried; to unload. 

weigh down

verb
  • To be too much for someone to cope with. 

  • To act as a ballast for. 

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