(a) NATURAL PERSONS. No tax upon estates or inheritances or upon the income of natural persons who are residents or citizens of the state shall be levied by the state, or under its authority, in excess of the aggregate of amounts which may be allowed to be credited upon or deducted from any similar tax levied by the United States or any state.

(b) OTHERS. No tax upon the income of residents and citizens other than natural persons shall be levied by the state, or under its authority, in excess of 5% of net income, as defined by law, or at such greater rate as is authorized by a three-fifths (3/5) vote of the membership of each house of the legislature or as will provide for the state the maximum amount which may be allowed to be credited against income taxes levied by the United States and other states. There shall be exempt from taxation not less than five thousand dollars ($5,000) of the excess of net income subject to tax over the maximum amount allowed to be credited against income taxes levied by the United States and other states.

(c) EFFECTIVE DATE. This section shall become effective immediately upon approval by the electors of Florida.