Last 12 month formula in Webi

Hi all guru,

I try to apply the below formula. There is an error occur where I can't put the 12 in the formula.

=(year(CurrentDate())12 + MonthNumberOfYear(CurrentDate())) - (year([Date])12 + MonthNumberOfYear([Date]))

My question is, how do i show last 12 month if i can't put the 12 in the formula??.

Regards,

Joseph