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The way the CFR varies by outbreak location, I tend to believe we’re seeing more virulent mutated strain in certain locations. Some attribute it to populations with more elderly, and smoking, etc, however I remember talk of different strains and now not so much.

I agree. The Case Fatality Rate (CFR) for CLOSED CASES (based on official published numbers) for various locations are listed below:

China - 4.3% (obviously bogus)
Italy - 44.0% (Overwhelmed)
Spain - 64.2% (Overwhelmed??)
United States - 65.7% (Low sample size)
Germany - 26.4% (Low sample size)
Iran - 16.9%
France - 22.1%
S. Korea - 3.8%
Switzerland - 81%
UK - 73.5%

For those who are comparing this to the published mortality rates, understand that the Mortality Rate and the Case Fatality Rate are not the same thing, even though their names might give the impression that they are. The numbers I've posted are calculated as deaths/closed cases, where a closed case is one where the patient either died or recovered. It does not include those who are still sick or who have the disease and remain undiagnosed. Thus, it answers a different question than statistics (like the mortality rate) that include those people. It answers the question If I am diagnosed with this disease, how likely am I to die from it?

CFR is also frequently calculated over a period of time, which is appropriate for diseases such as cancer. For example, it could be calculated to answer the question If I am diagnosed with pancreatic cancer, how likely am I to die within the next year?

So it is perfectly legitimate to calculate the statistic as I have. You just have to know what cases are included in the denominator to begin to understand the question that the number is answering.

Case Fatality Rates are used as one indication among several of the severity of an illness. A disease with a low CFR that is widely prevalent or contagious will not kill many people. On the other hand, a highly contagious disease with a high CFR can end up killing many, many people. And of course, the worst case scenario is a disease that is both highly contagious and has a high CFR. It is arguable, at least (and in my personal opinion, already demonstrated) that this is that case with COVID-19, or Coronavirus.

There are many factors that can influence a CFR. Here's a list of just some of them:

How many people have been tested
Ability of the local health care system to accurately diagnose the disease. This includes the accuracy of their testing methods.
The ability of the local health care system to accurately collect and report data. This includes the political will to be transparent.
The ability and willingness of political and health care decision makers to take early action.
The unique strain of the virus that is predominant in a given location
The ability of the health care system in that location to treat the number of patients with the disease. This includes numbers of hospital beds, availability of medications, ventilators, etc., number of uninfected health care personnel, etc.
The experience the medical personnel in any given area have with the disease, and their access to information from other professionals
The season of the year (although it's not clear that's relevant with Coronavirus, and there are indications it is not)
Genetics
The prevalence of other diseases and health conditions in the local community, including age, diabetes, obesity, lung disease (think of places with polluted air), poverty, malnutrition, etc.

I find it interesting to note that the only places with a CFR in the single digits (as I have calculated it) are in Asia. I don't know what that means. It could be simply bad data reporting. Or it could be a genetic factor.

Thanks for posting a concise and well written explanation of the difference between Mortality Rate and the Case Fatality Rate. This is very confusing to many.

Designed into the virus?

And...

Might a country planning a bio-weapon attack, given the technology, release a less virulent strain among their own populace prior to the attack on their enemy? This would would serve as a smoke screen, as well as to inoculate the majority of its own population from the more virulent and deadly strain to be released upon their enemy, shortly after.