Pursuant to the mandate of the "Municipal Home Rule Amendment" to the Constitution of this state, all municipal corporations are hereby classified by population into four classes, as follows:

(1) Every municipal corporation with a population in excess of fifty thousand shall be a Class I city;

(2) Every municipal corporation with a population in excess of ten thousand but not in excess of fifty thousand shall be a Class II city;

(3) Every municipal corporation with a population in excess of two thousand but not in excess of ten thousand shall be a Class III city; and

(4) Every municipal corporation with a population of two thousand or less shall be a Class IV town or village.

Transition from one to another class shall occur automatically when the requisite population qualification has been met, effective as of the effective date of the census, as specified in section four of this article.

The Legislature hereby declares its interpretation of the said "Municipal Home Rule Amendment" to be that a single classification by population of municipal corporations in this state is required which shall exclude any other classification of municipal corporations by population for any purpose. It is, therefore, the intention of the Legislature that the classification established in this section shall give effect to the Constitutional mandate and shall be the only classification by population applying to municipal corporations in this state. It is the further intention of the Legislature that subsequent legislation affecting municipal corporations in this state shall treat municipal corporations differently upon the basis of population, only in accordance with the general classification established in this section.