###HUMAN: what was the four most common specimen test ordered in this year?, ###ASSISTANT: SELECT t1.spec_type_desc FROM (SELECT microbiologyevents.spec_type_desc, DENSE_RANK() OVER (ORDER BY COUNT(*) DESC) AS c1 FROM microbiologyevents WHERE DATETIME(microbiologyevents.charttime, 'start of year') = DATETIME(CURRENT_TIME(), 'start of year', '-0 year') GROUP BY microbiologyevents.spec_type_desc) AS t1 WHERE t1.c1 <= 4