expressway vs throughway

expressway

noun
  • A road built to freeway standards. 

  • A divided highway, especially one whose intersections and direct access to adjacent properties have been eliminated. 

  • A road built for high speed traffic, but not up to motorway standards or designated a motorway. 

throughway

noun
  • A broad highway fit for high-speed traffic; a thoroughfare. 

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