only too vs so much

only too

adv
  • to a high degree; very well or very much 

  • very, all too. 

so much

adv
  • To a certain degree or extent 

adj
  • To such a quantity, degree etc. 

noun
  • A particular amount, often a large or excessive amount. 

  • A demonstrated amount. 

How often have the words only too and so much occurred in a corpus of books? (source: Google Ngram Viewer )