You can specify the x or y offset for each graph label individually by double-clicking it in the Graphics Viewer then clicking the Edit X offsets or Edit Y offsets button.
Ordinal
Displays the ordinal of the currently selected data point.
Offset
Displays the x or y offset associated with the current data point. Edit this number to change the offset.
Replace
Replaces the offset of the currently selected data point with the changed offset.
X/Y offsets
Displays a list of all the data points along with associated offsets for either the X or Y direction.