The inconsistency with the principle of equality determined in the second paragraph of Article 14 of the Constitution does not exist only in instances in which the legislature regulates differently states of facts that it should regulate in the same manner, but also in instances in which it regulates states of facts in the same manner for all, while there is no sound reason deriving from the nature of the matter for such. The legislature treated taxable persons that were in different factual positions in the same manner without a sound reason existing for such, as it adopted a regulation in accordance with which all taxable persons that in fact received either a higher or lower amount of subsidies compared to an average amount had an average amount of subsidies included in their tax bases. Therefore, the first to third paragraphs of Article 154 of the Personal Income Tax Act in the part in which they determined that an average amount of subsidies is included in tax bases were inconsistent with the second paragraph of Article 14 of the Constitution until they ceased to be in force.