Calculate the percentage of object samples that are related to street lights.
DIVIDE(COUNT(OBJ_SAMPLE_ID where OBJ_CLASS = 'street lights'), COUNT(OBJ_SAMPLE_ID)) as percentage;
SELECT CAST(SUM(CASE WHEN T2.OBJ_CLASS = 'street lights' THEN 1 ELSE 0 END) AS REAL) * 100 / COUNT(T1.OBJ_SAMPLE_ID) FROM IMG_OBJ AS T1 INNER JOIN OBJ_CLASSES AS T2 ON T1.OBJ_CLASS_ID = T2.OBJ_CLASS_ID
database name:db_id image_and_language
ATT_CLASSES table ATT_CLASSES Cols: ATTRIBUTE CLASS ID dtype integer, ATTRIBUTE CLASS dtype text, 
OBJ_CLASSES table OBJ_CLASSES Cols: OBJECT CLASS ID dtype integer, OBJECT CLASS dtype text, 
IMG_OBJ table IMG_OBJ Cols: IMAGE ID dtype integer, OBJECT SAMPLE ID dtype integer, OBJECT CLASS ID dtype integer, X dtype integer, Y dtype integer, W dtype integer, H dtype integer, 
IMG_OBJ_ATT table IMG_OBJ_ATT Cols: IMAGE ID dtype integer, ATTRIBUTE CLASS ID dtype integer, OBJECT SAMPLE ID dtype integer, 
PRED_CLASSES table PRED_CLASSES Cols: PREDICTION CLASS ID dtype integer, PREDICTION CLASS dtype text, 
IMG_REL table IMG_REL Cols: IMAGE ID dtype integer, PREDICTION CLASS ID dtype integer, OBJECT1 SAMPLE ID dtype integer, OBJECT2 SAMPLE ID dtype integer, 
