Here in Germany there's the statistic of "75% of infection sources are not found by tracing" circulating hard through public discussions. I doubt that many of those untraceable infections could be coming from symptomatic carriers, given the level of awareness. Coughing people basically do not exist in the 2020 public. And tracing should still be good enough to recognize most cases when the source became symptomatic after the contact (which would very likely be before the receiver became aware of the infection, triggering tracing). I consider this a pretty strong indication of asymptomatic spread, or very weakly symptomatic (thresholds are very subjective).