You could add the percentages as a new series, change it if necessary to a line series, then hide it by formatting it to have no lines and no markers. This will appear in the data table.
Or you could build a custom data table, either in the cells near the chart, or in any range somewhere else. You can add any information you want, and format it however you want. Then use the camera tool to copy the table and place it where you want it.
The camera tool button can be added to a toolbar like this: Tools menu > Customize > Commands tab, choose Tools in the left hand list, find the Camera tool on the right, and drag it to a convenient place in the toolbars.