The 80/20 Rule: A minority of input produces the majority of results

In 1906, Italian economist and avid gardener Vilfredo Pareto created a mathematical formula to describe the unequal distribution of wealth in his country. He observed that 20 percent of the people owned 80 percent of the wealth. While gardening, he later observed that 20 percent of the peapods in his garden yielded 80 percent of the peas that were harvested.