How can I filter for records whose sum make up X% of the total in Google Data Studio?

Question

I have a data set containing clients and two dimensions: Lifetime and Revenue, e.g.

Client	Lifetime	Revenue
Tesla	7,4	280
Amazon	9,2	450
Disney	2,6	130
Otto	11,8	940
BMW	3,5	170

I am trying to calculate the average lifetime, but instead of calculating the average over all clients, I only want to include the top clients (regarding revenue) whose sum of revenue make up 80% of the total revenue.

When doing this manually the process would be quite clear:

• Sort the clients by revenue descending
• Calculate the total revenue and thus what 80% of the total is
• Check at which row the running sum of the client's revenue exceeds that 80% and only include the records up to that point

This is what the resulting table would look like:

Client	Lifetime	Revenue	Running Sum of Rev
Otto	11,8	940	940
Amazon	9,2	450	1390
Tesla	7,4	280	1670
BMW	3,5	170	1840
Disney	2,6	130	1970

Since the total revenue is 1970, 80% of that would amount to 1576. Therefore I would want to select the top 3 (Otto, Amazon, Tesla) from the set, because their running sum (1670) is just bigger than the 1576. Then I could calculate the average lifetime of those three clients only.

I have no idea if this is possible in an automated way in Google Data Studio. Filters can only take absolute values and in datasets/blends the order is also not regarded.

Alternative: I would already be quite happy with something like including only the top 80% clients from the list of clients sorted by revenue (i.e. the 80% quantile). This would be the top 4 in the example (0.8 * 5 = 4), instead of the top 3 as of the original question, but that seems equally impossible.

Data Set (Google Sheets)

Google Data Studio Report