In Amidon v. Kane, 444 Pa. 38, 46, 279 A.2d 53, 58 (1971), our supreme court stated that "the constitutional imperative of uniformity in the imposition of taxes has remained unchanged since its first adoption in the Pennsylvania Constitution of 1874." Like that earlier constitution, Article VIII, Section 1 of the Pennsylvania Constitution today provides that: "All taxes shall be uniform, upon the same class of subjects, within the territorial limits of the authority levying the tax, and shall be levied and collected under general laws." Pa. Const., art. VIII, 1. Under the uniformity clause, absolute equality and perfect uniformity are not required. City of Harrisburg v. School District of Harrisburg, 551 Pa. 295, 303, 710 A.2d 49, 53 (1998). In cases where the validity of a classification for tax purposes is challenged, the test is whether the classification is based upon some legitimate distinction between the classes that provides a non-arbitrary and "reasonable and just" basis for the difference in treatment. Stated alternatively, the focus of judicial review is upon whether there can be discerned "some concrete justification" for treating the relevant group of taxpayers as members of distinguishable classes subject to different tax burdens. When there exists no legitimate distinction between the classes, and, thus, the tax scheme imposes substantially unequal tax burdens upon persons otherwise similarly situated, the tax is unconstitutional. Id. (quoting Leonard v. Thornburgh, 507 Pa. 317, 321, 489 A.2d 1349, 1352 (1985)). The taxpayer has a heavy burden to demonstrate that a challenged tax classification is unreasonable. Id.