aggravating circumstance vs oppression

aggravating circumstance

noun
  • A factor that increases the culpability or deleterious consequences of a wrongful act. 

oppression

noun
  • The exercise of authority or power in a burdensome, cruel, or unjust manner. 

  • The act of oppressing, or the state of being oppressed. 

  • A feeling of being oppressed. 

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