Customized Axis Labels

Implement the capability to add another measure or other value to an Axis Label. For instance, if you have a bar chart showing the % of total headcount by country, put the country name and the headcount numbers on the axis so users can easily see both values at once. This is often done in Excel by basing the chart on a calculation with cell references but I've never found a way to create a calculation for this in PBI.