bookshelf vs media center

bookshelf

noun
  • A shelf or shelves for storing books for easy visual reference. 

media center

noun
  • A school library that incorporates information technology as well as traditional print publications. 

  • A dedicated software application or hardware device for playback of audiovisual media in the home. 

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