Just as many sciences seek to understand large populations by analyzing a smaller representative sample of a population, the Bolshoi simulation focused on modeling a hypothetical representative volume of the universe.
The truth is that there can surely be no hard-and-fast rule for a country as diverse as America, 7% of whose population in a typical year will be exposed, according to Robert Ursano of the Uniformed Services University of the Health Sciences, to a traumatic event.