how to set my graph bar to be on bottom not at the center

my problem is when the amount have value 开发者_JAVA技巧the bar already set at the bottom but when the value is zero automatically my bar is set at the center...how i want to set my bar go to the bottom when amount is zero???

The maximum value on the Left Axis is set to Automatic by default. Uncheck Auto and set an explicit maximum value, and the chart will draw as expected.