Mo. Rev. Stat. § 233.215
Such special tax shall be apportioned against the lands in the district in the following manner: For the purpose of such apportionment, lands appearing by said list of lands as approved by the county commission to be within one-half mile of said public road or part of a public road, shall be given the valuation thereof indicated by said list, and lands more than one-half mile from and within one mile of said public road or part of a public road, seventy-five percent of the valuations thereof indicated by said list, and lands more than one mile and within one and one-half miles, fifty percent, and all over one and one-half miles, twenty-five percent of such valuations thereof; and the amount of the special tax assessed against each tract of said lands shall be such that the ratio between the amount assessed against each tract and the amount assessed against all of such tracts shall be the same as between the value so given each tract and the aggregate of the values so given all tracts in the district.
§ 233.215, RSMo