In Fosko v. Bd. of Assessment Appeals, 166 Pa. Commw. 393, 646 A.2d 1275, 1279 (Pa. Cmwlth. 1994), the taxpayer testified to the listing prices of the comparable properties but failed to present evidence of current market values, thereby precluding common pleas from determining whether the taxpayer's property was assessed at a different ratio than the comparables. The Court specifically opined: "Taxpayer's testimony regarding the real estate listing as opposed to sales prices of neighboring properties and speculation that some properties are of a greater value than his does not satisfy his burden of proof in rebutting the presumption of validity of the assessment." Fosko, 646 A.2d at 1280.