a bit vs not yet

a bit

adv
  • Slightly; rather. 

  • To a small extent; in a small amount. 

  • Very. 

  • A lot. 

not yet

adv
  • Not quite; not exactly. 

  • Not for the moment, though expected later. 

noun
  • A skill that one is learning but has not yet acquired. 

How often have the words a bit and not yet occurred in a corpus of books? (source: Google Ngram Viewer )