Postcodes in the same brick:
 

Mean 2007 2008 2009 Brick TC - - - n=1234  HDL - - -   LDL - - -         Division TC - - - n=5678  HDL - - -   LDL - - -         State TC - - - n=1256  HDL - - -   LDL - - -         National TC - - - n=2342  HDL - - -   LDL - - -