in question vs up in the air

in question

adj
  • In doubt, under dispute. 

  • Under consideration, under discussion. 

up in the air

adj
  • Not yet resolved, finished, answered, decided or certain. 

adv
  • Used other than figuratively or idiomatically: see up, in, the, air. 

How often have the words in question and up in the air occurred in a corpus of books? (source: Google Ngram Viewer )