create table #temp (customer varchar(15),number int)

insert into #temp select'A',10
insert into #temp select'B',20
insert into #temp select'C',17
insert into #temp select'D',18
insert into #temp select'E',30
insert into #temp select'F',40
insert into #temp select'G',10
insert into #temp select'H',20
insert into #temp select'I',17
insert into #temp select'J',18
insert into #temp select'K',30
insert into #temp select'L',40

select top 60 percent * from #temp
order by number desc

drop table #temp

declare @Total decimal(18,2)
select @Total = sum(number)
from #temp

create table #temp2
(
	customer varchar(15),
	number int,
	Ranking int
)

insert #temp2
select customer,
	Number,
	ranking = row_number() over(order by number desc)
from #temp

select customer,
	number,
	Running,
	pct = round((cast(Running as decimal(10,2))/ cast(@Total as decimal(10,2)))*100, 0)
from
(
	select customer, 
		number,
		Ranking = ntile(12) over(order by number desc),
		Running = (select sum(number) from #temp2 t1
		where t1.Ranking <= t.Ranking)
	from #temp2 t
)sub
where round((cast(Running as decimal(10,2))/ cast(@Total as decimal(10,2)))*100, 0) <= 60

drop table #temp2

DECLARE @Temp table (customer varchar(15),number int)
insert into @Temp select'A',10
insert into @Temp select'B',20
insert into @Temp select'C',17
insert into @Temp select'D',18
insert into @Temp select'E',30
insert into @Temp select'F',40
insert into @Temp select'G',10
insert into @Temp select'H',20
insert into @Temp select'I',17
insert into @Temp select'J',18
insert into @Temp select'K',30
insert into @Temp select'L',40

DECLARE @Sum INT

SELECT @Sum = SUM(number)
FROM @Temp

DECLARE @Percent FLOAT
SET @Percent = @Sum * .6

SELECT
	customer, Number, RunningTotal
FROM
	(
		SELECT 
			customer, 
			number,
			(
				SELECT SUM(Number) 
				FROM 
					(
						SELECT *,ROW_NUMBER() OVER (ORDER BY Number, Customer) AS RowNum 
						FROM @Temp
					) AS A
				WHERE RowNum <= T.RowNum
			) AS RunningTotal
		FROM 
			(SELECT *,ROW_NUMBER() OVER (ORDER BY Number, Customer) AS RowNum FROM @Temp) T
	) AS D
WHERE
	RunningTotal <= @Percent -- Could add on some sort of varience if needed
ORDER BY
	RunningTotal

create table #temp (customer varchar(15),number int)

insert into #temp select'A',1
insert into #temp select'B',1
insert into #temp select'C',1
insert into #temp select'D',1

drop table #temp