Abstract: Data on electric energy consumption of respective electric power consumers are collected in a predetermined period. Total electric energy consumption by the electric power consumers are classified into m levels. Degree of load contribution of the electric power consumers in consideration of at least load factors of the load factors which are ratios of average values of the consumed electric energy of the electric power consumers to the maximum values of the consumed electric energy and uniformity coefficient which are ratios of sum totals of the maximum values of the consumed electric energy of the electric power consumers belonging to the same level of consumed electric energy in the period are classified into n levels, the respective electric power consumers are divided into m×n number of classes and the result is displayed or stored.