Relative value in Crosstab in Business Objects WebI

Hi All,

I have an Cross tab report where I need to compare between Current Year data and Previous Year data. My table structure is like below:
       2012 2013 CY vs PY
US 100 150 
UK 250 230 
AUS 140 150 

Now, whenever I am trying to calculate Previous Year value through relative value function I am getting #computation error.

My formula =RelativeValue([measure];([Year]);-1)
Year is the dimension used horizontally in above crosstab.

Can you please suggest what I am missing here. Please provide your solution with Relative Value () only as this is only a prototype we are working on and Relative Value() is going to be required in large scale for the project.

Thanks in advance.