fewer vs not so much

fewer

det
  • Fewer women wear hats these days. 

not so much

phrase
  • Indicates that the speaker identifies with a prior statement to a much lesser degree (or not at all) than the other person. 

  • Indicates that one factor is much more relevant or important than another. 

How often have the words fewer and not so much occurred in a corpus of books? (source: Google Ngram Viewer )