instruction: what is the top five most frequent diagnosis since 6 years ago?
response: SELECT d_icd_diagnoses.short_title FROM d_icd_diagnoses WHERE d_icd_diagnoses.icd9_code IN (SELECT t1.icd9_code FROM (SELECT diagnoses_icd.icd9_code, DENSE_RANK() OVER (ORDER BY COUNT(*) DESC) AS c1 FROM diagnoses_icd WHERE DATETIME(diagnoses_icd.charttime) >= DATETIME(CURRENT_TIME(), '-6 year') GROUP BY diagnoses_icd.icd9_code) AS t1 WHERE t1.c1 <= 5)