middle vs periphery

middle

noun
  • The central part of a human body; the waist. 

  • A centre, midpoint. 

  • The part between the beginning and the end. 

  • The middle stump. 

  • The middle voice. 

adj
  • Pertaining to the middle voice. 

  • Located in the middle; in between. 

  • Central. 

periphery

noun
  • The outside boundary, parts or surface of something. 

  • A first-rank administrative division of Greece, subdivided into provinces. 

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