I need to calculate the cumulative percentage of n number of tasks completed under a parent row.

For example, I have 10 objects to report within three days and on the first day I report  4 objects, on the second day 3 objects and on the last day 3 objects. This means, 40% of the work is complete on the first day, 70% on the second day and 100% on the third. 

Is it possible to show the cumulative percentage on the parent row ?

Thank you