hogan vs shelter

hogan

noun
  • A one-room Navajo dwelling or ceremonial lodge, constructed of wood and earth and covered with mud. 

shelter

noun
  • A refuge, haven or other cover or protection from something. 

  • An institution that provides temporary housing for homeless people, battered women, etc. 

verb
  • To take cover. 

  • To provide cover from damage or harassment; to shield; to protect. 

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