instruction: since 05/14/2103, list the yearly maximum sao2 of patient 028-7951.
response: SELECT MAX(vitalperiodic.sao2) FROM vitalperiodic WHERE vitalperiodic.patientunitstayid IN (SELECT patient.patientunitstayid FROM patient WHERE patient.patienthealthsystemstayid IN (SELECT patient.patienthealthsystemstayid FROM patient WHERE patient.uniquepid = '028-7951')) AND NOT vitalperiodic.sao2 IS NULL AND STRFTIME('%y-%m-%d', vitalperiodic.observationtime) >= '2103-05-14' GROUP BY STRFTIME('%y', vitalperiodic.observationtime)