What layer of the earth composes 80 percent of the lithosphere27s volume?

The mantle is the layer of the Earth that composes about 80% of the lithosphere's volume. It is a solid layer of rock that lies beneath the Earth's crust and extends down to the outer core. The lithosphere, which includes the crust and uppermost part of the mantle, is broken into tectonic plates that float on the semi-fluid asthenosphere below.