[tinco]

I think the better solution would be to use 2 pie charts, in the first group all < 5% clients in one category "Other". In the second just map other. (again grouping clients < 5% of the other category, but not mapping them).

I think the suggestion to use a timeline series is not a good idea, pie charts are perfect for visualizing complementing percentages.

If you really want to visualize the movement of the percentages use a stacked percentage chart like this one:

http://www.highcharts.com/demo/area-stacked-percent

Ofcourse I would suggest 2 again, one for the big clients and one for the small ones :)