The resonance has an isospin and as a strong interaction resonance, the decay channels are treated in the PDG as one "Nucleon pi" decay
From the isospin argument one would expect 50% and 50% split between the two channels of the 100%The correct ratio is given in the tableanswer by @Thomas, because conservationwho gives the algebra of charge does not allow other combinationsthe SU(2) isospin case. 2:1