instruction: what percentile of the po2 value is a 75.0 among a patient of the same age as patient 6170 on this hospital encounter?
response: 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 = 'po2') AND labevents.hadm_id IN (SELECT admissions.hadm_id FROM admissions WHERE admissions.age = (SELECT admissions.age FROM admissions WHERE admissions.subject_id = 6170 AND admissions.dischtime IS NULL))) AS t1 WHERE t1.valuenum = 75.0