what was the average value of patient 76005's rapamycin since 87 months ago?
select avg(labevents.valuenum) from labevents where labevents.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 76005 ) and labevents.itemid in ( select d_labitems.itemid from d_labitems where d_labitems.label = 'rapamycin' ) and datetime(labevents.charttime) >= datetime(current_time,'-87 month')