On the left axis are the number of active cases in Davidson County (where I am right now). The right axis and the red line is the percentage of people in the county that have tested positive for COVID-19. The inflection point on the graph seems to be around 2.2% of the population.
What I think we’re looking at is the first glimmer of herd immunity. The estimates I’ve seen is that the under-count is 6-24x. With 24x that would be around 72% of the people in this county have already had it.