Here it is by hours first:
select
Convert(varchar(2), [EndDate],114) as hh,count(*) from [dbo].[Vote] group by Convert(varchar(2), [EndDate],114)
order by Convert(varchar(2), [EndDate],114)
And now by days:
select
Convert(varchar(8), [EndDate],112) as dd,count(*) from [dbo].[Vote] group by Convert(varchar(8), [EndDate],112)
order by Convert(varchar(8), [EndDate],112)