XSLT 1.0 Grouping

Question

I need to apply XSLT 1.0 transformation to following XML:

  
    2013
    

        

Answer 1

Please try this:

When run on this input:

  
    
      2013
      13
      13
    
    
      2012
      12
      12
    
  
  
    
      2013
      13
    
    
      2011
      11
    
  

The result is:

  
    2013
    13
    13
    13
  
  
    2012
    12
    12
    
  
  
    2011
    
    
    11