I'm not sure about how CR 10 is set up, but you should be able to choose the name field as your row, sum of your amount field as your first summary, and then add the amount field again as a second summary and then click on "change summary" and choose options->check "Show as a percentage of" and check "row".
If you want to display these summaries horizontally, go to the customize style tab->summaries->check "horizontal" and "show labels".
If you add a column field, you would have to take a different approach.
-LB