Allow display of ratio data on bar chart

[JulietK]

It would be really helpful to be able to display simple calculation of ratio, percentage data etc on bar charts. 

For example in the Indicator widget, its possible to get and display a ratio of count of values in Field A and sum of value B (reference here). However it would be really useful if I could do the same in a bar chart, and show the ratio data per category. 

e.g. Worker productivity (ratio) = amount (count) of work output / sum of time worked

For now I have a indicator widget set up to display the amount of work output, and the Worker Productivity (ratio) data per worker, by using Side Panel Selector of the list of worker names. Primary issue here is that I can only see worker productivity data one worker at a time - if I could configure a bar chart to show the values from the Worker Productivity ratio data, with one axis listing the worker names and the other axis showing values, it would be great. 

I imagine similar type of configuration would also be useful for display of other simple calculated values like percentages.