By April 1956 half of the members of the Urban Council were elected, but by a minority of the population. A voter had to be at least 21 years of age, to have lived in Hong Kong for at least three years and to be qualified in at least one of 23 categories, which included educational qualifications (School Certificate Examination or equivalent), be a juror, salaried taxpayer, or a member of certain professional organisations. More details can be found in Schedule 1 of the "Urban Council Ordinance" (Cap. 101, "Laws of Hong Kong"). It was estimated that in 1970 there were 250,000 eligible voters and in 1981 the number had increased to 400,000 – 500,000.