coulee vs ravine

coulee

noun
  • A deep gulch or ravine, frequently dry in summer. 

  • A stream. 

  • A lava flow. 

  • A reach of water in a bayou that is like a slough but deeper. 

ravine

noun
  • A deep narrow valley or gorge in the earth's surface worn by running water. 

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