debitage vs leaf litter

debitage

noun
  • The sharp-edged waste material that remains after creation of a stone tool 

leaf litter

noun
  • Dead plant material, such as fallen leaves, bark, and twigs, that has fallen to the ground and may be used by animals as habitat or for nest-building, eventually decomposing and releasing nutrients into the soil. 

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