I thought this would be easy, but I am really stumped!

I need to show the percentage in addition to the value in the data labels
for a line chart.

Example,
January February
Series 1 5 6
Series 2 15 4

I would like the January data label for Series 1 to show 5 (25%)
I would like the January data label for Series 2 to show 15 (75%)

I would like the February data label for Series 1 to show 6 (60%)
I would like the February data label for Series 2 to show 4 (40%)

TIA FOR ANY HELP!