I am trying to recreate the below bar graph (from Excel) in Domo. In the below picture, the orange bar shows the 'Billed Amount' for that day (numbers along the bottom represent the day of the month). The gray bar shows the cumulative amount billed thus far that month (i.e. the second gray bar shows the sum of Day 1 and Day 2's Billed Amounts, the third gray bar shows the sum of Day 1, 2, and 3 Billed Amounts, and so on).

Thus far I have been unable to come up with a beast mode in Domo that will calculate this cumulative bar. Surely this must be possible; I am assuming I'm just missing something.
Any help, suggestions, or advice would be appreciated!
Thanks!