What percentage of the intensity gets through both polarizers?

if the two polarizers have the same direction the transmitted light is 50% of the incident and if the two polarizers are at 90º the transmitted light is zero

Explanation:

The incident light is generally random, that is, it does not have a polarization plane, when the first polarized stops by half, this already polarized light arrives at the second polarizer and the causticity passes

I = I₀ cos² θ

therefore if the two polarizers have the same direction the transmitted light is 50% of the incident and if the two polarizers are at 90º the transmitted light is zero