And when you don’t know what 80:20 rule means, that’s when Wikipedia comes to the rescue.

The Pareto principle (also known as the 80:20 rule, the law of the vital few and the principle of factor sparsity[1][2]) states that, for many outcomes, roughly 80% of consequences come from 20% of causes (the “vital few”).[1]

https://en.wikipedia.org/wiki/Pareto_principle