what is the percentile of 13.8 for a white blood cells test given the same age of patient 96833 on their current hospital encounter?
select distinct t1.c1 from ( select labevents.valuenum, percent_rank() over ( order by labevents.valuenum ) as c1 from labevents where labevents.itemid in ( select d_labitems.itemid from d_labitems where d_labitems.label = 'white blood cells' ) and labevents.hadm_id in ( select admissions.hadm_id from admissions where admissions.age = ( select admissions.age from admissions where admissions.subject_id = 96833 and admissions.dischtime is null ) ) ) as t1 where t1.valuenum = 13.8