what is the daily average phosphate value for patient 25951 since 2105?
select avg(labevents.valuenum) from labevents where labevents.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 25951 ) and labevents.itemid in ( select d_labitems.itemid from d_labitems where d_labitems.label = 'phosphate' ) and strftime('%y',labevents.charttime) >= '2105' group by strftime('%y-%m-%d',labevents.charttime)