apropos vs for sake of

apropos

prep
  • Regarding or concerning. 

adj
  • Of an appropriate or pertinent nature. 

  • by the way, incidental 

adv
  • To the purpose; appropriately. 

  • By the way. 

  • Timely; at a good time. 

for sake of

prep
  • Because of, for the sake of. 

How often have the words apropos and for sake of occurred in a corpus of books? (source: Google Ngram Viewer )