calculate the number of patients who had received a fiber-optic bronchoscopy procedure until 1 year ago.
select count( distinct admissions.subject_id ) from admissions where admissions.hadm_id in ( select procedures_icd.hadm_id from procedures_icd where procedures_icd.icd9_code = ( select d_icd_procedures.icd9_code from d_icd_procedures where d_icd_procedures.short_title = 'fiber-optic bronchoscopy' ) and datetime(procedures_icd.charttime) <= datetime(current_time,'-1 year') )