How many more children were born per woman  in Singapore in 2012 compared to Ethnic Chinese in 2004?
return Singapore ;return Ethnic Chinese ;return children born per woman of #1 ;return children born per woman of #2 ;return #3 in   2012 ;return #4 in   2004 ;return the  difference of #5 and  #6
['select', 'select', 'project', 'project', 'filter', 'filter', 'arithmetic']