How to calculate cummulative value according to specific data in a tabular data

Question

Hello everyone,

So, I want to get a cummulative sum for each week (there is 15 week in total) according to the data in "Route" column.
The picture above is how i would like to calculate the cummulative, but i want to do it in power query because the original data is too big to handle in excel.

Thank you in advance