You should do the value of 2016 minus the value of 2010, let's call this field 'Difference'.
Then you need to create a dual axis where the you need only the 2010 value on the shelf, change this chart to gantt chart and put the 'Difference' field onto size. Even if there's a decrease it should be fine because the difference would be a negative value.
Please see my attached workbook, it should help you build this type of chart:
Gantt_v10.2.twbx 7.4 MB
Thanks Mavis this worked a treat!