what is the number of times patient 28966 has received a glucose lab test until 2103?
select count(*) from labevents where labevents.itemid in ( select d_labitems.itemid from d_labitems where d_labitems.label = 'glucose' ) and labevents.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 28966 ) and strftime('%y',labevents.charttime) <= '2103'