197.152 Collection of unpaid or omitted taxes; interest amount; taxable value.—Unpaid or omitted taxes shall be collected upon the basis of the regular valuation placed by the property appraiser upon the land for the year for which taxes remain unpaid, and, when no valuation was so placed, then the last assessed valuation prior thereto shall be considered the regular valuation. Omitted taxes shall be paid with interest thereon at the rate of interest specified in this chapter.