culpability vs onus

culpability

noun
  • The degree of one's blameworthiness in the commission of a crime or offence. 

onus

noun
  • Blame. 

  • A legal obligation. 

  • Burden of proof, onus probandi. 

  • Stigma. 

  • Responsibility; burden. 

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