The 80/20 rule is not a formal mathematical equation, but more a generalized phenomenon that can be observed in economics, business, time management, and even sports. General examples of the Pareto principle: 20% of a plant contains 80% of the fruit. 80% of a company's profits come from 20% of customers.
70.0%United States of America (the)
14.6%Russian Federation (the)
10.2%China