Ohio Rev. Code Ann. § 319.33

The county auditor need not assess on the taxable property of the county, or of any township, municipal corporation, or school district in such county, for any purpose, any rate of taxation containing or resulting in any fraction other than a decimal fraction or in any decimal fraction less than one-tenth of a mill, but if the sum required to be raised for any purpose results in a fraction less than one-twentieth of a mill, such fraction shall be dropped, and if more than one-twentieth and less than one-tenth, the difference between such fraction and one-tenth of a mill shall be added to the fraction.