A post $$ tensioned prestressed concrete beam of rectangular section $100$mm wide and $300$mm deep and spanning $10$m is stressed by successive tensioning and anchoring of two cables numbered $1$ and $2$ respectively. The cross $$ sectional area of each cable is $200$ sq$.$mm and the initial stress in the cable is $1200$ MPa. Modular ratio is $6.$ The first cable is parabolic with an eccentricity of $50$mm below the centroidal axis at the center of the span and $50$mm above the centroidal axis at the support sections. The second cable is also parabolic with an eccentricity of $50$mm towards the bottom at the center of the span and concentric at the support sections. Estimate the percentage loss of stress in each of these cables due to elastic deformation of concrete only if they are successively tensioned and anchored.