apropos vs bang on

apropos

adj
  • Of an appropriate or pertinent nature. 

  • by the way, incidental 

adv
  • To the purpose; appropriately. 

  • By the way. 

  • Timely; at a good time. 

prep
  • Regarding or concerning. 

bang on

adj
  • Precisely accurate; exactly appropriate or fitting; spot on. 

verb
  • To constantly talk about something. 

prep
  • Exactly at 

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