ulster vs winter coat

ulster

noun
  • A long, loose overcoat made of wool or other rough material, often called a greatcoat, which sometimes features an attached shoulder cape covering the back and sleeves, and which can sometimes be buttoned in front. 

winter coat

noun
  • A warm coat, often an overcoat, fit to be worn in winter 

  • An animal's seasonal appearance in winter, notably thicker and/or otherwise camouflaged plumage or fur after (often autumnal) moulting 

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