what is the five, the most frequent input event until 2101?
select d_items.label from d_items where d_items.itemid in ( select t1.itemid from ( select inputevents_cv.itemid, dense_rank() over ( order by count(*) desc ) as c1 from inputevents_cv where strftime('%y',inputevents_cv.charttime) <= '2101' group by inputevents_cv.itemid ) as t1 where t1.c1 <= 5 )