dunnage vs traps

dunnage

noun
  • Scrap material, often wood, used to fill spaces to prevent the shifting of more valuable items during transport, or underneath large or heavy items to raise them slightly above the ground, in order to protect from chafing and wet. 

  • Personal effects; baggage. 

traps

noun
  • A trap set. 

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