PROC HPBIN computes the 0% (minimum), 1%, 5%, 10%, 25%, 50%, 75%, 90%, 95%, 99%, and 100% (maximum) percentiles of each binning variable.
Let 
 be the number of nonmissing values for a variable, and let 
, 
, ..., 
 represent the ordered values of the variable. Let the 
th percentile be 
, set 
, and let 
 = 
 + 
, where 
 is the integer part of 
 and 
 is the fractional part of 
. Then the 
th percentile is as described as: 
         
Note: To avoid the time-consuming sorting process, the HPBIN procedure uses an iterative projection method to compute percentiles according to the preceding formula.