T-SQL (SS2K8) :: Percentile With NTILE(100) For Less Than 100 Observations - How To Display On 100 Scale

I have process and people want to know percentile rank (on scale of 100), I'm bit lost as I have cases when I have let say 5 observations, so if use code below I can not got above number of observations:

Is there any way to get that numbers like RankWanted ??

; WITH cte AS (
SELECT 100 Cust_ID , 0.338129 Perc, 20 RankWanted union
SELECT 300 Cust_ID , 0.487179 Perc, 40 RankWanted union
SELECT 300 Cust_ID, 0.500000 Perc, 60 RankWanted union
SELECT 400 Cust_ID, 0.541666 Perc, 80 RankWanted union
SELECT 500 Cust_ID, 0.548780 Perc, 100 RankWanted )
SELECT Cust_ID, Perc,

[code].....