keffiyeh vs tabard

keffiyeh

noun
  • A headdress traditionally worn by some Arabs, also used as a scarf. 

tabard

noun
  • A sleeveless garment made of coarse cloth formerly worn outdoors by the common people. 

  • A cape or tunic worn by a knight, emblazoned with the coat of arms of his king or queen on the front. 

  • A similar garment officially worn by a herald and emblazoned with his sovereign's coat of arms. 

  • A silk banner attached to a bugle or trumpet. 

  • A sleeveless jerkin or loose overgarment. 

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