Another important data point to assess testing is Case Fatality Rate (CFR). This is about 2.5% in the SF Bay Area.
In other places with higher testing, such as Australia, the CFR is 0.6% or less. This implies that the true number of cases is 4-5 times higher... probably a lot more.
It seems like this disease is so successful because of a significant symptom-free-but-contageous period followed by a small percentage of very serious symptoms.
That's what a pandemic needs. If it is very deadly very quickly it kills its transmission vectors before they can transmit. If it is entirely symptom free, it is very evolutionarily successful, but no one cares because there aren't any negative effects.
There is an "optimum" of disease characteristics for maximum damage and we seem to be experiencing one.
The bottom line is that it seems to be very difficult to prevent a majority of the world population from getting this disease and the result is going to be a global fatality rate of somewhere in the neighborhood of 1%.
What put it into perspective for me is the CDC estimate of up to 25% cases being entirely asymptomatic [1], and data from Iceland shows 50% of those tested were asymptomatic at time of testing [2].
It will be hard to trace and isolate if this is the case.
That also doesn't account for the exponential growth in number of cases; the people dying now are out of a much smaller cohort of confirmed cases in the past.
Deaths / (Deaths + Recoveries) would be more like it, and that's a scary number.
In other places with higher testing, such as Australia, the CFR is 0.6% or less. This implies that the true number of cases is 4-5 times higher... probably a lot more.