Question: What percentage of businesses are in the Real Estate sector and have the rating of 5 out of all businesses in Chandler?
SQL: SELECT CAST(SUM(CASE WHEN T1.stars = 5 THEN 1 ELSE 0 END) AS REAL) * 100 / COUNT(T1.business_id) AS "percentage" FROM Business AS T1 INNER JOIN Business_Categories ON T1.business_id = Business_Categories.business_id INNER JOIN Categories AS T3 ON Business_Categories.category_id = T3.category_id WHERE T1.city LIKE 'Chandler' AND T3.category_name LIKE 'Real Estate'