make out vs scratch the surface

make out

verb
  • To discern; to manage to see, hear etc. 

  • To manage, get along; to do (well, badly etc.). 

  • To draw up (a document etc.), to designate (a cheque) to a given recipient, payee. 

  • To represent; to make (something) appear to be true. 

  • To embrace and kiss passionately. 

  • To engage in heavy petting or sexual intercourse. 

scratch the surface

verb
  • To barely begin; to see or do only a fraction of what is possible. 

How often have the words make out and scratch the surface occurred in a corpus of books? (source: Google Ngram Viewer )