How many percentage less people identified as Christian in 2015 compared to 2006?
return people ;return #1 identified as Christian ;return #2 in  2015 ;return #2 in  2006 ;return percentage of #3 ;return percentage of #4 ;return difference of #6 and  #5
['select', 'filter', 'filter', 'filter', 'project', 'project', 'arithmetic']