have a break vs sit back

have a break

verb
  • To have a short rest period from work, study, etc. 

sit back

verb
  • To relax, to not exert oneself. 

  • To recline while still in a seated position, with one's back on the frame of the seat. 

How often have the words have a break and sit back occurred in a corpus of books? (source: Google Ngram Viewer )