Mo. Rev. Stat. § 137.070
In all counties in this state which have now or may hereafter adopt township organization, if the amount of revenue desired and estimated by the county commission for county purposes and the amount desired and estimated by any township board for township purposes shall together exceed the rate percent on the one hundred dollars valuation allowed by Section 11 of Article X of the Constitution of Missouri for county purposes, then it shall be the duty of the county commission to apportion the tax for county purposes between the county organization and the township organization in the following manner, to wit: Eighty percent of the taxes which may be legally levied for county purposes shall be apportioned to the county organization for county purposes, and twenty percent of such taxes shall be apportioned to the township organization for the purposes provided by section 65.360 of the township organization law, as specified by the township board; but the combined rate for both the county and township organizations shall not exceed the maximum rate provided by the constitution.
§ 137.070, RSMo