prolocutor vs vox populi

prolocutor

noun
  • A spokesman, one who speaks on behalf of others. 

  • A chairman of the lower house of a convocation in the Anglican Church. 

vox populi

noun
  • The public comment portion of a public meeting. 

  • voice of the people. 

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