Ammonia gas at a pressure of 20 atm and ${27}^{0}C$  is heated in a constant volume in a container to a temperature of ${327}^{0}C$ at which new pressure becomes 50 atm and the following equilibrium  $2N{H}_{3\left(g\right)}\underset{ }{\rightleftharpoons }{N}_{2\left(g\right)}+3H_{2\left(g\right)}$ is established. The percentage dissociation of ammonia at this temperature is