stack bar char is showing more than 100% value

[ashis]

Hello guru,

I have one stack bar chart and ,it has 5 expression as excellent , average , good , poor, below average .

Problem i am facing if I sum up all the values it is going more than 100%

Please see the attached screen shot. I need to make it such a way it should not go beyond 100% and all the values should match to 100.

Kindly advise