HJR 2006:

-Requires a bill that increases the individual income tax rate or corporate income tax rate, or the rate of any other type of tax based upon income or legal and special reserves, to be adopted by at least two-thirds of the members elected to each house of the general assembly. 

-A tax on income or based upon income for individuals shall be imposed at a single rate if imposed, and a graduated rate of taxation on such income is prohibited.