Here is a sample using SET ANALYSIS to dynamically calculate the most recent year in the user's selection and show that year's actual sales as the needle in the gauge while adding a green reference line to denote the previous years actual sales
Also attached is the QVF for your inspection. Just put it in your My Documents\qlik\sense\apps directory to see it in the destkop hub.
Note that on load i parsed your Year values to just show the first four characters ( ex: 2013/14 -> 2013) . That made it easy to calculate the most recent year in the user's selection (ie: max(year) and previous year (ie : max(year)-1) .
You can load both year formats and use a different field name for each if you want .