Ammonia is synthesized commercially from nitrogen gas and hydrogen gas for the production of fertilizers: N2..?

Ammonia is synthesized commercially from nitrogen gas and hydrogen gas for the production of fertilizers: N2 (g) +3H2(g) -> 2NH3 (g). If 100.0 g of nitrogen reacts completely with excess hydrogen, and 34.0 g of NH3, are obtained, what is the percent yield of ammonia?