only too vs somewhat

only too

adv
  • very, all too. 

  • to a high degree; very well or very much 

somewhat

adv
  • Very. 

  • To a limited extent or degree. 

noun
  • More or less; a certain quantity or degree; a part, more or less; something. 

  • A person or thing of importance; a somebody. 

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