What this expression means

[arethaking]

max(all aggr(Sum({$<Year={$(=Max(Year))}>}  Sales/$(vCurrency)) / Sum({$<Year={$(=Max(Year))}>}  Budget_$(vCurrency)), Customer))

[oknotsen · Accepted solution]

Of the maximum year in your current selection, calculated the Sales divided by the Budget and do this for every Customer. Take the maximum value of that list.