when was patient 97330 last having the maximum epithelial cells level since 16 months ago?
select labevents.charttime from labevents where labevents.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 97330 ) and labevents.itemid in ( select d_labitems.itemid from d_labitems where d_labitems.label = 'epithelial cells' ) and datetime(labevents.charttime) >= datetime(current_time,'-16 month') order by labevents.valuenum desc, labevents.charttime desc limit 1