doner kebab vs shish kebab

doner kebab

noun
  • A Turkish dish in which meat (typically seasoned lamb or mutton, but alternatively chicken or perhaps beef) is grilled on a revolving vertical spit; when cooked, the meat is sliced off and served with fresh vegetables in pita or rolled in a piece of unleavened flatbread. 

shish kebab

noun
  • A dish made of small pieces of meat, with or without vegetables, which are skewered on a wooden or metal stick and roasted in an oven or over an open fire. 

  • A crystal structure consisting of a central spine (the shish) and disks or lumps growing out from it (the kebab). 

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