what is the average total cost of the hospital that includes testing in the reticulocyte count, manual laboratory since 5 years ago?
select avg(t1.c1) from ( select sum(cost.cost) as c1 from cost where cost.hadm_id in ( select labevents.hadm_id from labevents where labevents.itemid in ( select d_labitems.itemid from d_labitems where d_labitems.label = 'reticulocyte count, manual' ) ) and datetime(cost.chargetime) >= datetime(current_time,'-5 year') group by cost.hadm_id ) as t1