Each category on the category axis is identified by a label and separated from other categories by tick marks. You can change the intervals at which labels and tick marks appear. For 2-D charts, you can specify where you want the value (y) axis to cross the category (x) axis.
Click the category axis you want to change.
On the Format menu, click Selected Axis, and then click the Scale tab.
Select the options you want.
Tip To have the edges of an area chart meet the edges of the plot area, clear the Value (Y) axis crosses between categories check box.