what dose of calcium gluconate was last prescribed to patient 95470 since 12/2102?
select prescriptions.dose_val_rx from prescriptions where prescriptions.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 95470 ) and prescriptions.drug = 'calcium gluconate' and strftime('%y-%m',prescriptions.startdate) >= '2102-12' order by prescriptions.startdate desc limit 1