comforter vs eiderdown

comforter

noun
  • A padded cover for a bed, duvet, continental quilt. 

  • A pacifier. 

  • A person who comforts someone who is suffering. 

eiderdown

noun
  • A quilt stuffed with this down. 

  • The down of the eider duck, used for stuffing pillows and quilts. 

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