Answer

1. Drag [Sales] to the Columns shelf
2. Drag [Sub-Category] to the Rows shelf
3. Drag [Order Date] to Color on the marks card
4. Drag [Order Date] to the Filter shelf
5. In the Filter Field dialog, select Years and click Next >
6. In the Filter dialog, check only 2014 and 2015 and click OK
7. On the marks card, in the drop-down, select Circle
8. Create a calculated field with a name like "2015 Sales" with a calculation similar to the following:

   { FIXED [Sub-Category] : SUM
   (
   IF YEAR([Order Date]) = 2015
   THEN [Sales]
   END
   ) }

9. Create a calculated field with a name like "Difference" with a calculation similar to the following:

   { FIXED [Sub-Category] : SUM(
   IF YEAR([Order Date]) = 2014
   THEN [Sales]
   END
   ) }
   -
   [2015 Sales]
   

10. Drag [2015 Sales] to the Columns shelf.
11. Click [2015 Sales] on the Columns shelf to open the SUM(2015 Sales) marks card.
12. In the SUM(2015 Sales) marks card, do the following:
    1. In the dropdown, select Gantt Bar
    2. Remove YEAR(Order Date) from Color
    3. Drag [Difference] to Size
    4. Optional: click Size and adjust the thickness of the bar with the slider.
13. Right-click [2015 Sales] on the Columns shelf and select Dual Axis
14. Right-click the Sales axis at the bottom of the view and select Move marks to front
15. Right-click [2015 Sale] on the Columns shelf and un-check Show Header

Additional Information