Easily above 20% would be my guess. However, the more important point is this: It doesn't matter. If you ask this to know how much weight to lose to see your abs, I'm sorry to disappoint you but that's nearly impossible to predict. Most people also lose a fair bit of water, glycogen and a bit of muscle while dieting so they always end up having to lose more weight than they thought they'd have to. Time to go to work.