autoroute vs freeway

autoroute

noun
  • An expressway, freeway, motorway or highway. 

  • An expressway in any Francophone country. 

freeway

noun
  • A toll-free highway. 

  • A highway with grade-separated crossings (rather than level crossings) and designed (and only permitted) for high-speed motor-traffic running in two directions on one separate carriageway each 

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