Question: In reviews of product with 5 stars, what is the percentage of the reviews coming from the division of East North Central?
SQL: SELECT CAST(SUM(CASE WHEN T1.division = 'East North Central' THEN 1 ELSE 0 END) AS REAL) * 100 / COUNT(T1.division) FROM district AS T1 INNER JOIN reviews AS T2 ON T1.district_id = T2.district_id WHERE T2.Stars = 5