Mo. Rev. Stat. § 288.038

With respect to initial claims filed during calendar years 2004 and 2005, the "maximum weekly benefit amount" means four percent of the total wages paid to an eligible insured worker during that quarter of the worker's base period in which the worker's wages were the highest, but the maximum weekly benefit amount shall not exceed two hundred fifty dollars in the calendar years 2004 and 2005. With respect to initial claims filed during calendar years 2006 and 2007 the "maximum weekly benefit amount" means four percent of the total wages paid to an eligible insured worker during that quarter of the worker's base period in which the worker's wages were the highest, but the maximum weekly benefit amount shall not exceed two hundred seventy dollars in calendar year 2006 and the maximum weekly benefit amount shall not exceed two hundred eighty dollars in calendar year 2007. With respect to initial claims filed during calendar year 2008 and each calendar year thereafter, the "maximum weekly benefit amount" means four percent of the total wages paid to an eligible insured worker during the average of the two highest quarters of the worker's base period, but the maximum weekly benefit amount shall not exceed three hundred twenty dollars. If such benefit amount is not a multiple of one dollar, such amount shall be reduced to the nearest lower full dollar amount.