The exit age distribution for a reactor is given by E(t) = $\delta$(t-4), where t is in seconds. A first order liquid phase reaction (k = 0.25 s$^{-1}$) is carried out in this reactor under steady and isothermal conditions. The mean conversion of the reactant at the exit of the reactor, up to 2 digits after the decimal point, is $\_\_\_\_\_\_\_$