bier vs body bag

bier

noun
  • A litter to transport the corpse of a dead person. 

  • A platform or stand where a body or coffin is placed. 

  • A count of forty threads in the warp or chain of woollen cloth. 

body bag

noun
  • A non-porous bag designed to contain a human body, used for the storage and transport of corpses. 

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