I guess it's time for some math explanations: The formula for the volume of a sphere is (4/3)*Pi*r^3. The radius of the Earth is 3,963.1676 miles. The deepest point in the ocean is 6.85625 miles below the surface. If we were to assume that the entire globe was covered by water, and that the depth of that water were 6.85625 miles deep at all points, then the non-water volume of the earth would be 259,394,041,162 cubic miles. The total volume of the earth (water included) would be 260,744,961,822 cubic miles, giving us a difference of 1,350,920,661 cubic miles, which means that, even given this very favorable water scenario, water would still only make up about one half of one percent of the earth's total volume.