(a) During the ad valorem tax year beginning October 1, 1978, with respect to any ad valorem tax levied by a county, municipality, or other taxing authority other than the state, the governing body of any such county, municipality, or other taxing authority may at any time, effective for ad valorem tax years beginning on and after October 1, 1978, increase or decrease the ratio of assessed value to the fair and reasonable market value or, as may otherwise be provided by law, to the current use value, as the case may be (herein called "the assessment ratio"), of any class of taxable property within the limits prescribed in the Constitution; provided, that the county, municipality, or other taxing authority meets the criteria contained in this section. If the receipts from any ad valorem tax with respect to which any assessment ratio has been so adjusted by any taxing authority during the ad valorem tax year beginning October 1, 1978, exceed by more than five percent, or are less than 95 percent of, the receipts from such ad valorem tax for the ad valorem tax year beginning October 1, 1977, then for the ad valorem tax years beginning on and after October 1, 1979, the taxing authority may adjust any assessment ratio with respect to such ad valorem tax in the manner provided for adjustments made during the ad valorem tax year beginning October 1, 1978. On and after October 1, 1979, the governing body of any county, municipality, or other taxing authority may at any time increase or decrease the assessment ratio applicable to any class of taxable property; provided, that any proposed adjustment to an assessment ratio to be made pursuant to this sentence, whether an increase or a decrease, shall have been (1) proposed by the governing body of the taxing authority after a public hearing on such proposal, (2) thereafter approved by an act of the Legislature and (3) subsequently approved by a majority vote of the qualified electors residing in the taxing authority who vote on the proposal at a special election called and held in accordance with the law governing special elections; and provided further, that the county, municipality, or other taxing authority meets the criteria contained in this section.

(b) In determining whether any assessment ratio applicable to any class of taxable property may be increased or decreased by any such county, municipality, or other taxing authority pursuant to this section, the following criteria shall be applied:

(1) If, on any October 1, the total assessed value of all property classified in any one class of taxable property located in the county, municipality, or other taxing authority constitutes more than 50 percent of the assessed valuation of all taxable property in the county, municipality, or other taxing authority, the assessment ratio with respect to that class of taxable property may be decreased up to a maximum of five percent differential from the rates set forth in subsection (a) of Section 40-8-1, as amended.

(2) If, on any October 1, the total assessed value of all properties classified in any one class of taxable property located in the county, municipality, or other taxing authority constitutes less than 20 percent of the assessed valuation of all taxable property in the county, municipality, or other taxing authority, the assessment ratio with respect to that class of taxable property may be increased up to a maximum of five percent differential from the rates set forth in subsection (a) of Section 40-8-1, as amended.

(3) If, on any October 1, the total assessed value of all properties classified in any one class of taxable property located in the county, municipality, or other taxing authority constitutes more than 75 percent of the assessed valuation of all taxable property in the county, municipality, or other taxing authority, the assessment ratio with respect to that class of taxable property may be decreased up to a maximum of five percent differential, and each assessment ratio of properties classified in any class of taxable property other than the aforementioned class of taxable property may be increased up to a maximum of five percent differential, from the rates set forth in subsection (a) of Section 40-8-1, as amended.

(c) Any action authorized by this section to be taken by a taxing authority or the governing body thereof shall, if there is no such governing body, be taken by resolution of the governing body of the county in which such taxing authority is located acting on behalf of such taxing authority.