Specifies how bars and columns are positioned. Can be a value between – 100 and 100. Applies only to 2-D bar and 2-D column charts. Read/write Long.
Remarks
If this property is set to – 100, bars are positioned so that there's one bar width between them. If the overlap is 0 (zero), there's no space between bars (one bar starts immediately after the preceding bar). If the overlap is 100, bars are positioned on top of each other.