Is it possible to calculate percent each bucket value represents of the whole?

I would like to be able to calculate percentage of each bucket's value (bucket value divided by the sum of all buckets values).

For example if I aggregate store sales by store calculating total $ per store and I want it in % of total sales rather than absolute $ values

I was hoping a pipeline aggs would do it for me but it does not seem so. I have not used pipelines before so I may be missing some way of doing it

your suggestion is appreciated