leaf through vs read through

leaf through

verb
  • To turn the pages of (a book) idly, reading short sections at random. 

read through

verb
  • To thoroughly read something to check or proofread it 

  • To read and obey a signal that is beyond the applicable one (often mistakenly) 

  • To read a script out loud casually with other actors but without blocking 

How often have the words leaf through and read through occurred in a corpus of books? (source: Google Ngram Viewer )