instruction: how many patients have received a ck-mb index test since 2101?
response: SELECT COUNT(DISTINCT admissions.subject_id) FROM admissions WHERE admissions.hadm_id IN (SELECT labevents.hadm_id FROM labevents WHERE labevents.itemid IN (SELECT d_labitems.itemid FROM d_labitems WHERE d_labitems.label = 'ck-mb index') AND STRFTIME('%y', labevents.charttime) >= '2101')