The historical data window, in which these historical data are entered, is accessed by clicking on the button History in the Demand Forecast window. The first time this Historical data window is accessed, there is a single line in the corresponding table. This line is associated to the current yearly period. The data corresponding to the different periods can then be entered. It can be seen that the graph is immediately updated. If the data for the first month of the first year are not available, corresponding cells can be left empty: Calculation starts with the first non null data.
Note: The Demand Forecasting module uses the historical data that are anterior to the current date exclusively. Furthermore, if elements of the most recent data are missing (for example data associated to the latest quarter), the Demand Forecasting module takes this fact into account and automatically estimates the sales forecasts for the future periods from the available data.