Definition
The Demand infotype stores information on the number of business events of a particular type that is required in a specific time period.
Validity specifications
The following specifications apply to the validity of infotype records:

If the validity start date you specify is not 01/01 of the year, a warning is displayed. You may ignore the warning.
Use
The Demand infotype is used in conjunction with the planning function. The report
business event demand lists the demand that exists for selected business event types, sorted by language and by location.Structure
You can create demand per quarter, per location, and per language.
Integration
You maintain this infotype in Customizing for Training and Event Management under Business Event Preparation or in Current Settings under Create Business Event Type. Alternatively, you can create demand when you carry out business event planning in the Planning Menu.

You have the option of creating the Demand infotype or determining what demand there is for events when you plan business events in the Planning menu.
See also:
Demand Determination