How can I calculate the Average Stock based on this table?

LY Actual Plan Seasonal Sales $ GA 2,011.2 $ 2,095.7 Sales inc./dec% 4.2% Alteration and Workroom Costs 2.8% 3.0% Cash Discount % 3.5% 4.0% Calculate - use 3.25 for Basic Stock Method Plan Seasonal Stock Turnover 2.1% 2.0% Shortage % Average Stock Average Monthly Sales Markdown % Employee Discounts% Initial MU% GMROI 3 Profit GM% SEOM for July 6 $335.2 18.8% 4.5% 58.6% $349.3 21.0% 4.0% 60.6% 10.0% 48.8% $747.7 14.0% 51.0% $755.0 Feb Mar Apr May June July Sales 285.5$ 311.3$ 298.7 $ 325.5$ 444.5$ 345.7 BOM LY (actual) LY (actual) LY (actual) 723.5 1021.4 822.1 845.7 1138.7 897.7 Reduction% 12.5% 15.0% 14.5% 17.0% 23.0% 18.0% LY Actual Plan Seasonal Sales $ GA 2,011.2 $ 2,095.7 Sales inc./dec% 4.2% Alteration and Workroom Costs 2.8% 3.0% Cash Discount % 3.5% 4.0% Calculate - use 3.25 for Basic Stock Method Plan Seasonal Stock Turnover 2.1% 2.0% Shortage % Average Stock Average Monthly Sales Markdown % Employee Discounts% Initial MU% GMROI 3 Profit GM% SEOM for July 6 $335.2 18.8% 4.5% 58.6% $349.3 21.0% 4.0% 60.6% 10.0% 48.8% $747.7 14.0% 51.0% $755.0 Feb Mar Apr May June July Sales 285.5$ 311.3$ 298.7 $ 325.5$ 444.5$ 345.7 BOM LY (actual) LY (actual) LY (actual) 723.5 1021.4 822.1 845.7 1138.7 897.7 Reduction% 12.5% 15.0% 14.5% 17.0% 23.0% 18.0%