Mekko Graphics includes the ability to add a gridlines to your chart. Gridlines draw across the entire chart and may be either vertical or horizontal or both, depending on the chart type.
TO ADD GRIDLINES
Check the Gridlines checkbox in the General tab of the Format Chart Task Pane. You can also add gridlines via the Format Axes Task Pane per axis.
Go to the Style tab of the Format Chart Task Pane. Here, you may format the line color, width, and style.