A metallic strain gauge of resistance $R_X$ with a gauge factor of 2 is bonded to a structure made of a metal with modulus of elasticity of $200\: GN/m^2$. The value of $R_X$ is $1\:k\Omega$ when no stress is applied. $R_X$ is a part of a quarter bridge with three identical fixed resistors of $1\:k\Omega$ each. The bridge is excited from a DC voltage of 4 V. The structure is subjected to a stress of $100\:MN/m^2$. Magnitude of the output of the bridge (in mV, rounded off to two decimal places) is _________.