bast vs oakum

bast

noun
  • Fibre made from the phloem of certain plants and used for matting and cord. 

oakum

noun
  • A material, consisting of tarred fibres, used to caulk or pack joints in plumbing, masonry, and wooden shipbuilding. 

  • The coarse portion separated from flax or hemp in hackling. 

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