humanities vs liberal arts

humanities

noun
  • The study of language, literature, the arts, history, and philosophy, sometimes including religion. 

liberal arts

noun
  • The academic course of instruction intended to provide general knowledge and usually comprising the arts, humanities, natural sciences, and social sciences, as opposed to professional or technical subjects. 

  • The trivium and the quadrivium. 

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