Except as provided in this section, the Legislature shall not impose a sales tax on retailers at a rate of more than 4% of their gross taxable sales of tangible personal property.

     Beginning May 1, 1994, the sales tax shall be imposed on retailers at an additional rate of 2% of their gross taxable sales of tangible personal property not exempt by law and the use tax at an additional rate of 2%. The proceeds of the sales and use taxes imposed at the additional rate of 2% shall be deposited in the state school aid fund established in section 11 of this article. The allocation of sales tax revenue required or authorized by sections 9 and 10 of this article does not apply to the revenue from the sales tax imposed at the additional rate of 2%.

     No sales tax or use tax shall be charged or collected from and after January 1, 1975 on the sale or use of prescription drugs for human use, or on the sale or use of food for human consumption except in the case of prepared food intended for immediate consumption as defined by law. This provision shall not apply to alcoholic beverages.