The Design Team were considering how we could add this to the spending screen a while ago now, but so far we haven’t found a solution we’re satisfied with. As Hugo explained early last year, a lot of this is to do with the subconscious associations of percentages and financial products (interest rates and charges) , and also the fact that without a fixed order of magnitude (how much you load onto your card each month for example) it would be hard to accurately compare your spending stats month to month referring to percentage data.