cotton wool vs padding

cotton wool

noun
  • Soft, absorbent cotton for medical or cosmetic use, protective padding, etc. 

  • Raw fibers of cotton before being processed. 

padding

noun
  • Soft filling material used in cushions etc. 

  • Extra characters such as spaces added to a record to fill it out to a fixed length. 

  • Extraneous text added to a message for the purpose of concealing its beginning, ending, or length. 

  • Anything of little value used to fill up space. 

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