Need to show percentages next to numbers in charts

Hey all,

So I have a bar chart with numbers as its data labels...so each bar is divided into 4 colors equaling to 100% ...how can i show percentages next to numbers in the chart...so for example if a bar equals to 200 and each color is lets say 20, 60, 40, 80 ...i would like to show these numbers as well as percentages..i know we can do this manually by inserting a text box but the percentages might change quite often and i dont want to go through the hassle of calculating and changing them each time.