What is the percentage of the object samples in the class of "man" in image no.1?
object samples refers to OBJ_SAMPLE_ID; class of "man" refers to OBJ_CLASS = 'man'; image no.1 refers to IMG_ID = 1; percentage = divide(count(OBJ_SAMPLE_ID)when OBJ_CLASS = 'man', count(OBJ_SAMPLE_ID)) as percentage
SELECT CAST(COUNT(CASE WHEN T1.OBJ_CLASS = 'man' THEN 1 ELSE NULL END) AS REAL) * 100 / COUNT(T1.OBJ_CLASS_ID) FROM OBJ_CLASSES AS T1 INNER JOIN IMG_OBJ AS T2 ON T1.OBJ_CLASS_ID = T2.OBJ_CLASS_ID WHERE T2.IMG_ID = 1