apropos vs as it is

apropos

adv
  • To the purpose; appropriately. 

  • By the way. 

  • Timely; at a good time. 

prep
  • Regarding or concerning. 

adj
  • Of an appropriate or pertinent nature. 

  • by the way, incidental 

as it is

adv
  • Used other than figuratively or idiomatically: see as, it, is. 

  • In the actual circumstances (and often contrary to expectations). 

  • Already; without adding further difficulty or complexity. 

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