In the case of a real property tax appeal, no taxpayer shall be deemed aggrieved by an assessment, nor shall an assessment be lowered or an exemption allowed, unless there is shown:
(1) Assessment of the property exceeds by more than 10 percent the market value of the property;
(2) Lack of uniformity or inequality, brought about by illegality of the methods used or error in the application of the methods to the property involved;
(3) Denial of an exemption to which the taxpayer is entitled and for which such person has qualified; or
(4) Illegality, on any ground arising under the Constitution or laws of the United States or the laws of the State or the ordinances of the city in addition to the ground of illegality of the methods used, mentioned in subdivision (2).
(Sec. 8-12.3, R.O. 1978 (1987 Supp. to 1983 Ed.)) (1990 Code, Ch. 8, Art. 12, § 8-12.3) (Am. Ord. 96-58)