... or the 80/20 principle was coined in the early 1900s by Vilfredo Pareto, an Italian economist. He observed that the pea pods in his garden were producing peas at this rate. 20 percent of the pea pods produced 80 percent of the peas. This output was then observed by him on a larger scale, across industries, societies and companies.
This principle states that 80 percent of the output or results comes from 20 percent of the input or effort.