title: Expression to find value for previous year SSRS
body: <p>I need some help with expressions.I need a report that shows calcul of a field for current year as well as previous year respecting this rule expression(Last-Last Previous)/Last Previous*100. Also the report runs on a Year Parameter. 
  Below is an example for the result<br>
  for example i selected the years 2010 2011 2012</p>
  
  <pre><code>       year
   Data        2010    2011   2012  
   hp          14      25     30    
   Dell        17      18     20 
  </code></pre>
  
  <p>and the result i want</p>
  
  <pre><code>     year
   Data        2010    2011   2012  2011/2012 
   hp          14      25     30       0.002     (Last -Last Previous)/(last Previous*100) =(30-25)/(25*100) 
   Dell        17      18     20       0.0040  
  </code></pre>
  
  <p>How can i do this </p>
  
  <pre><code>SELECT 
    NON EMPTY 
      {[Measures].[Val]} ON COLUMNS
   ,NON EMPTY 
      {
        [DimCAT].[lbl].[lbl].ALLMEMBERS * [DimDate].[Year].[Year].ALLMEMBERS
      } ON ROWS
  FROM [Data];
  </code></pre>