A concrete beam of span $15\: m,\ 150\: mm$ wide and $350\: mm$ deep is prestressed with a parabolic cable as shown in the figure (not drawn to the scale). Coefficient of friction for the cable is 0.35, and coefficient of wave effect is $0.0015$ per meter.

If the cable is tensioned from one end only, the percentage loss (round off to one decimal place) in the cable force due to friction, is ________.