how to make an expression

[#1]

Hi,

  Everyone,I have a problem about making a chart like below,

Comments:

Levels:A、B、C            (with the sales data)

So, how to write the expression with a chart in the Sample?

Best Regards!

[#2]

thanks a lot , but the Level is dynamic, so it does not calculate in the code ,but in the expression.

[#3]

so, I  worked it out. Thanks for all your help.