in question vs reliable

in question

adj
  • Under consideration, under discussion. 

  • In doubt, under dispute. 

reliable

adj
  • Suitable or fit to be relied on; worthy of dependence, reliance or trust; dependable, trustworthy 

  • Such that either a sent packet will reach its destination, even if it requires retransmission, or the sender will be told that it didn't 

noun
  • Something or someone reliable or dependable 

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