What is Pareto’s (80-20) rule of automation?

Vilfredo Pareto was an Italian engineer-sociologist who, in the 19th century, studied the number of people in various income classes and represented his findings in diagrams. His conclusion was that 80% of the total wealth in the world is owned by 20% of people and that 20% of wealth is owned by 80% of people. A similar pattern is observed in other problem areas where 20% of the causes contribute to 80% of the problem. The specific Pareto’s (80-20) rule for automation is, however, unheard of.