QUESTION
A report contains a chart and it should be changed in a way that in the chart each column value also includes the total from the previous columns. So e.g. if a report is monthly, a bar chart would contain
Column 1 : Value for January
Column 2 : Value for February + January
Column 3 : Value for March +February + January
etc...
RESOLUTION
Cognos provides the keyword running-total to achieve this. E.g. if the value to report on is in the column 'TaskCountPerMonth', then create an expression ' running-total( TaskCountPerMonth )' in order to get the cumulative values.