conscience vs moral code

conscience

noun
  • A personification of the moral sense of right and wrong, usually in the form of a person, a being or merely a voice that gives moral lessons and advices. 

  • The moral sense of right and wrong, chiefly as it affects a person’s own behaviour and forms their attitude to their past actions. 

moral code

noun
  • A written, formal, and consistent set of rules prescribing righteous behavior, accepted by a person or by a group of people. 

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