until 56 months ago, what was the yearly maximum weight of patient 7519?
select max(chartevents.valuenum) from chartevents where chartevents.icustay_id in ( select icustays.icustay_id from icustays where icustays.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 7519 ) ) and chartevents.itemid in ( select d_items.itemid from d_items where d_items.label = 'admit wt' and d_items.linksto = 'chartevents' ) and datetime(chartevents.charttime) <= datetime(current_time,'-56 month') group by strftime('%y',chartevents.charttime)