What percentage of a meteor would burn up as it passes through the Earth's atmosphere?

[campbelp2002]

It depends on the speed and direction of the incoming object and how strong it is. If it is a weak ball of dust it could be quite large and completely disintegrate in the air, but if it is a small blob of nickel-iron it might loose very little mass before hitting the ground. If it comes in slowly enough it might loose almost none of it's mass. For example space craft like the Shuttle are designed to get hot without loosing any of their mass and they enter the atmosphere at a very shallow angle and a slower speed than a meteor. The Apollo capsules returning from the Moon hit the atmosphere at the same speed as the slowest possible meteor but also did so at a very shallow angle and so that only a tiny percentage of the mass of the heat shield was lost.