oakum vs sisal

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. 

sisal

noun
  • The fibre of the plant. 

  • A sisal mat. 

  • A Central American plant, Agave sisalana, cultivated for its sword-shaped leaves that yield fibers used for rope. 

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