navigable vs travelable

navigable

adj
  • Seaworthy; in a navigable state; steerable. 

  • Easy to navigate. 

  • Steerable, dirigible. 

  • Capable of being navigated; deep enough and wide enough to afford passage to vessels. 

travelable

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