when did the last procedure time of patient 18841 the previous year?
select procedures_icd.charttime from procedures_icd where procedures_icd.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 18841 ) and datetime(procedures_icd.charttime,'start of year') = datetime(current_time,'start of year','-1 year') order by procedures_icd.charttime desc limit 1