secondary school vs university

secondary school

noun
  • In the UK and Ireland, a state school attended between the ages of 11 and 16 or 18. 

  • School with education level between primary school and university. 

  • The federally designated, graduation-separated classification of grades 9–12 (approximately ages 14–18), regardless of whether they are compiled together in one school or separate from the other grades. 

  • Middle school; junior high school; a school that one attends between the ages of 12-17 (equivalent of grades 7-10 in North America, and years 7-10 in Australia). 

university

noun
  • Institution of higher education (typically accepting students from the age of about 17 or 18, depending on country, but in some exceptional cases able to take younger students) where subjects are studied and researched in depth and degrees are offered. 

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