academic institution vs middle school

academic institution

noun
  • An educational institution, dedicated to teaching and/or research. 

  • An educational institution, dedicated to higher education and research, that grants academic degrees. 

middle school

noun
  • A school which crosses the traditional divide between primary school and secondary school. 

  • An educational level or stage between primary school and secondary school. 

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