clam diggers vs shorts

clam diggers

shorts

noun
  • pants or trousers worn for sports or in warmer weather that do not go lower than the knees. 

  • Short, inferior hemp. 

  • The part of milled grain sifted out which is next finer than the bran; pollard. 

  • Remnants, clippings, trimmings of production processes. 

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