Actually, here's what I see on a typical vaping prep, for THC but not CBD: TOT THC: 80.94%. Tot THC: 809.42mg. Tot CBD: 0.00mg. The CBD ones typically have between 65% and 99% CBD. Each container has a traceability mark and these things are tested in-house with calibrated equipment.

That said, I buy from a premium dispensary and I have no idea what's vended in smoke shops.