This style of chart applies when you have more than one series. The Stacked property specifies how the two sets of values are displayed in relation to each other. In the Chart Type tag, specify one of:
none. Only one series is displayed.
clustered. The two series are displayed separately. This is the default.
stacked. The series are displayed "stacked" on top of each other.
stacked percent. The series are stacked and shown as a percentage