It is extremely variable. A pair of 99% white pieds can throw a 1% white pied baby and a pair of 1% white pieds can throw a 99% white pied. The amount of white in the parents has no impact on the amount of white the babies have. That is not to say that a certain pairing will not only produce high white or low white. That is something I can not speak on but I would think that would be a possibility.