what is the average value of reticulocyte count, automated in patient 15794's body during this month?
select avg(labevents.valuenum) from labevents where labevents.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 15794 ) and labevents.itemid in ( select d_labitems.itemid from d_labitems where d_labitems.label = 'reticulocyte count, automated' ) and datetime(labevents.charttime,'start of month') = datetime(current_time,'start of month','-0 month')