Select at least one Y column of values (or a range from at least one column). If there is an associated X column, X column supplies X values; otherwise, sampling interval of the Y column or row number is used.
Select required data.
Select Plot > Bar, Pie, Area: 100% Stacked Area from the main menu.
StackAreaP.OTP (installed in the Origin program folder).
When one Y column of values (or a range from one column) is selected, the area between the data plot and the "From" Y axis value is filled by default, no normalization is performed. When multiple Y columns (or ranges) are selected, all columns are normalized and cumulated to 100%. And each successive normalized column is displayed as an area graph that is stacked on the previous area. The upper bounds of the first area is treated as the baseline of the next area.
Other than plotting a 100% stacked area graph from 100% Stacked Area menu directly, you can also plot it from a stacked area graph: check the Normalize to Percent for Cumulative/Incremental checkbox in the Stack Tab of Plot Details dialog.