shish kebab vs shishkebab

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). 

shishkebab

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