1. A Sales History Decomposition method comprising: mapping definition of sales data; time slotting of the sales data; aggregating the sales data; initial estimating of a trend in the sales data; computing de-trended sales history using the trend estimate; regressing to remove price, seasonal, and marketing instruments effects; removing the estimated seasonal, price and marketing instrument effects from the sales data; re-estimate trend effects from the sales data having the removed estimated seasonal, price and marketing instrument effects; and computing a de-trended and de-seasonalized sales data.