gyratory vs traffic circle

gyratory

noun
  • A large traffic roundabout with non-standard lane markings or priorities, or with buildings on the central island. 

adj
  • Moving in a circle, or spirally; revolving; whirling around. 

traffic circle

noun
  • an intersection with a circular shape and, usually, a central island 

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