Accordingly, the taxpayer was liable for the sales and use tax on those materials. The Tennessee Supreme Court has recognized the Department's long use of what is known as the "51 percent rule" to determine whether a taxpayer who manufactures goods at any location is primarily a "manufacturer" for purposes of the exemption provided by section 67-6-206. Alley-Cassetty Coal Co. v. Johnson, No. M2003-02327-COA-R3-CV, 2005 WL 729180, at *4 (Tenn.Ct.App. Mar. 29, 2005)( no perm. app. filed) (citing Tenn. Farmers' Coop. v. State, 736 S.W.2d 87, 89 (Tenn. 1987)). Under this rule, the taxpayer is entitled to the exemption provided by ยง 67-6-206 if the fabricating or processing of tangible personal property produces at least 51 percent of the total revenue at that location.