How many at a minimum millions of dollars more did Yemen receive from the U.S. in 2009 than 2006?
return Yemen ;return minimum millions of dollars #1 did receive ;return #2 from  the  U.S. ;return #3 in  2009 ;return #3 in  2006 ;return the  number of  #4 ;return the  number of  #5 ;return the  difference of #6 and  #7
['select', 'project', 'filter', 'filter', 'filter', 'aggregate', 'aggregate', 'arithmetic']