The catholic/Nationalist population in the time of the Unionist dictatorship was 35% rising to 40%, around the mid 1950s, the Nationalists had the large amount of 3 seats in Stormont.
The city of Derry 75% Nationalist was never able to have control of the Counncil due to discrimination and the Prime Minister Basil Brooke had earlier told Unionists that" he wouldn`t have one about the place" he was referring to Catholics. Every constituency was gerrymandered to ensure the Unionist remained solidly in control.
If the "vote early vote often" label was applied to Nationalists how come they never seemed to wangle control of Derry, at one time the Unionist population of West Belfast [Shankill Road area] was half as much again after each election, there was the famous quote by Eddie Mc`Ateer that"the dead arose and voted for many".