Show all branch names with the number of members in each branch registered after 2015.
return branch  ;return when  #1 registered ;return #1 where #2 is  after 2015 ;return members ;return number of  #4 for each #3 ;return names of #3 ;return #6 ,  #5
['select', 'project', 'comparative', 'select', 'group', 'project', 'union']