1. All counties of this state are hereby classified, for the purpose of establishing organization and powers in accordance with the provisions of § 8, Article VI , Constitution of Missouri, into four classifications determined as follows:

Classification 1. All counties having an assessed valuation of nine hundred million dollars and over shall automatically be in the first classification after that county has maintained such valuation for the time period required by section 48.030; however, any county of the second classification which, on August 28, 2010, has had an assessed valuation of at least six hundred million dollars for at least one year may, by resolution of the governing body of the county, elect to be classified as a county of the first classification after it has maintained such valuation for the period of time required by the provisions of section 48.030.

Classification 2. All counties having an assessed valuation of six hundred million dollars and less than the assessed valuation necessary for that county to be in the first classification shall automatically be in the second classification after that county has maintained such valuation for the time period required by section 48.030.

Classification 3. All counties having an assessed valuation of less than the assessed valuation necessary for that county to be in the second classification shall automatically be in the third classification.

Classification 4. All counties which have attained the second classification prior to August 13, 1988, and which would otherwise return to the third classification after August 13, 1988, because of changes in assessed valuation shall remain a county in the second classification and shall operate under the laws of this state applying to the second classification.

2. The required assessed valuation for each classification under subsection 1 of this section shall be increased annually by an amount equal to the percentage change in the annual average of the Consumer Price Index for All Urban Consumers (CPI-U) or zero, whichever is greater. The state tax commission shall calculate and publish this amount so that it is available to all counties.