I would try your Category as first dimension, year second dimension.
Two expressions calculating blend QTY and stock.
Choose the appropriate (Stacked) style in style tab.
Hope this helps,
If you have many years in your year dimension and you want to filter only this and last year, try a calculated dimension like
=if(Year=year(today()) or Year=year(addmonths(today(),-12)), Year)
edited by swuehl