. It wouldn't even be 8%
It will be greater because thrust is to the square of the change in velocity. The formula is
F = .5 * r * A * [Ve ^2 - V0 ^2] where Ve is the air velocity downstream of the prop and V0 is the velocity upstream of the the prop. However there is a loss from drag on the prop to the square of the surface area of the prop, but the latter is a smaller number.