I will say that people who are really social and uses the internet everyday will almost 100% have heard about bitcoin... They may necessarily not know so much but they will have a vague idea if what it is.
   The level of understanding is based on them and how they have done their research.. the older generations may not be actively involved due to the risk of losing funds and being scammed but the "gen z" possibly knows what bitcoin is about... Anyone who at this time doesn't know about bitcoin, could be due to their age or pure negligence to follow the advancement of the world.