Hard to say. There are tons of studies on the subject and they all have different findings. The number of asymptomatic covid positive people who got tested was found to be between 5% and 90% (not talking about pre-symptomatic, aka people who developed symptoms in the next weeks).

There seems to be a correlation with age, the younger you are, the less likely you have symptoms.

Considering that asymptomatic people are less likely to be tested than people with symptoms, this is a lower bound.

I'm inclined to believe the majority of cases are asymptomatic and that therefore that most people don't notice it.