high school vs intermediate school

high school

noun
  • Secondary school. 

  • An institution which provides all or part of secondary education. 

intermediate school

noun
  • A school for children that serves grades between elementary school and high school, and occasionally between the former and middle school. These grades vary from anywhere from grade 4 to grade 8. 

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