The Current Stats
As of March 14, 2020
Since the publishing of the WHO's "Coronavirus disease" report, (https://www.who.int/docs/default-source/coronaviruse/situation-reports/20200306-sitrep-46-covid-19.pdf?sfvrsn=96b04adf_2) the estimated mortality rate has been published and repeated in the media as approximately "3-4%". However, the formula that is commonly used appears to be inherently flawed.
The equation used by organizations like the WHO project their estimates using "the number of reported deaths divided by the number of infections". This formula doesn't account for the projected percentage of deaths included in the number of those effected. Dividing reported deaths (5,539) by the total confirmed cases (147,838), resolved cases gives an arbitrarily low figure of 3.7%.
If we were to divide the Total Deaths by Total Recovered cases we would receive a figure closer to the trending global mortality rate of 7.7% and allows us to project deaths more accurately. As detailed between both sources (Johns Hopkins and WorldOMeters), this result coincides with the anticipated mortality rates (7-8%) based on "Active" and "Critical Cases" used for this equation.
When examining past events like the Spanish Flu, we have the benefit of hindsight and total compiled data to form an accurate estimate of a pandemic's global mortality rate. Unfortunately, without complete data, and only using theoretical estimates for unreported cases, the best we can do is produce formulas that take into account, total cases, recovered cases and total deaths, which appear to trend closer to 7-8%.