What is the difference between cell walls of Gram positive and Gram negative bacteria?

The cell wall of Gram positive bacteria is single layered (outer membrane is absent) and contains 70-80% peptidoglycan and little amount of lipids. It’s wall also has teichoic acid.
The light cell wall of Gram negative bacteria on the other hand is two layered, outer membrane is present, i.e., thin layer of peptidoglycan and plasma membrane is present, teichoic acid is absent in wall.