I've noticed a lot of people go a step ahead and say it's 90-10 or 95-5 for them. Between the lines, it seems they think it must add up to 100. It doesn't have to. The 80 applies to one area (revenue) while the 20 applies to another (work). It can be 77% and 17% for all you know. 77% of revenue coming from 17% of clients or 92% of revenue coming from 14% of clients.