Why is vapour pressure of solution of glucose in water lower than water?

The vapour pressure of a pure solvent decreases /lowers when a non- volatile solute is added to the solvent.This is because, on adding the solute, a fewer number of water molecules are present at the surface which can evaporate as some of the surface area is occupied by non- volatile solute molecules thereby decreasing the vapour pressure of the solution.Thus, the vapour pressure of the solution of the glucose in water is lower than that of water