The easiest way I know of to show yr2015, yr2016 and the delta between is that you create two worksheet and merge them on dashboard.
Sort by Year Field
Add table calc
Add same table calc to other three fields.
Change index to discrete and put it on filter shelf and pick "0" to show only the latest year.
Hide headers with with checking-off "show header"
2015,2016_9.2.twbx 43.9 KB
What is that index dimension that you have in your example?
It's just to set the last year.