We do have one population in which we have complete testing data (for active infection, not residual antibodies): the crew of the USS Theodore Roosevelt. Among them 60% of those infected were asymptomatic. No info in the source I read on how many of the other 40% had only such minor symptoms that they'd be passed over as a mere flu or bad cold had they not been in a circumstance with universal testing.
Seeing that out in the general population we're only testing people who are either front-line medical staff or who have come down with at least two of the big three symptoms (fever, dry cough, difficulty breathing), it's almost certain that there are a lot more people who have had or now have the virus than are showing up in our statistics.