In Conlen Grain and Mercantile, Inc. v. Texas Grain Sorghum Producers Bd., 519 S.W.2d 620 (Tex. 1975), agricultural producers voted under the Texas Commodity Referendum Act to create a board that levied assessments to be used for developing research programs, disease control, education, and marketing. Under the Act, the board was expressly an agency of the state. This Court held that the assessment was an occupation tax that violated Article VIII, Section 1 of the Texas Constitution, which prohibited an occupation tax on an agricultural pursuit. Conlen Grain, 519 S.W.2d at 624. During the course of our opinion in Conlen Grain, we said that one reason the assessments constituted a tax was because their primary purpose was to generate revenue to be used by an agency of the state and that the agency could use that revenue as it considered proper for public purposes: The assessments on producers are levied periodically to provide a fairly constant source of revenue that is expended by an agency of the state as it considers proper for the support of programs calculated to increase the production and use of particular agricultural commodities. These programs doubtless promote the economic welfare of many who are engaged in producing the commodities, but the assessment paid by any particular person is not necessarily related to the benefits that will be received by that person through the Board's expenditure of the money he paid. The levy is not a special assessment. Id. at 623. The Court then said that because the power of the state was used to deprive commodity producers of money or at least the use of money until the assessment was refunded, and because the primary purpose of the assessment was to raise revenues, it was a tax. Id.