apology vs exoneration

apology

noun
  • An expression of remorse or regret for having said or done something that harmed another: an instance of apologizing (saying that one is sorry). 

  • A formal justification, defence. 

  • Anything provided as a substitute; a makeshift. 

exoneration

noun
  • An act of disburdening, discharging, or freeing morally from a charge or imputation. 

  • The state of being disburdened or freed from a charge. 

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