variables in Qliksense

vCurrOrders=Sum{{<Year={$(=max(Year))}>}distict OrderID)

vPrevOrders=Sum{{<Year={$(=max(Year)-1)}>}distict OrderID)

KPI expression:

num((($(vCurrOrders)-$(vPrevOrders))/$(vCurrOrders)),'##0.0%') is not working,

It worked in Qlikview with = sign before num, but it is not working in QS. I don't know why.

Please help me