for the last time in 01/last year, when was patient 1912 prescribed for atorvastatin?
select prescriptions.startdate from prescriptions where prescriptions.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 1912 ) and prescriptions.drug = 'atorvastatin' and datetime(prescriptions.startdate,'start of year') = datetime(current_time,'start of year','-1 year') and strftime('%m',prescriptions.startdate) = '01' order by prescriptions.startdate desc limit 1