As at 31 March
 As at 30 June
 As at 30 September
 As at 31 December
 For the three-month periods ended 31 March
 For the six-month periods ended 30 June
 For the nine-month periods ended 30 September
 For the years ended 31 December
  2012
Quarter1
  2011
Quarter1
Quarter2
Quarter3
Year
  2010
Quarter1
Quarter2
Quarter3
Year
  2009
Quarter1
Quarter2
Quarter3
Year
  2008
Quarter1
Quarter2
Quarter3
Year
  2007
Quarter1
Quarter2
Quarter3
Year
  2006
Quarter1
Quarter2
Quarter3
Year
  2005
Quarter1
Quarter2
Quarter3
Year