what is in 06/2101 average pt value of patient 73206?
select avg(labevents.valuenum) from labevents where labevents.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 73206 ) and labevents.itemid in ( select d_labitems.itemid from d_labitems where d_labitems.label = 'pt' ) and strftime('%y-%m',labevents.charttime) = '2101-06'