comforter vs duvet

comforter

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

  • A pacifier. 

  • A person who comforts someone who is suffering. 

duvet

noun
  • A quilt or usually flat cloth bag with a filling (traditionally down) and usually an additional washable cover, used instead of blankets; often called a comforter or quilt, especially in US English. 

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