What is the ratio of having the best to worse elite user in 2013?
best elite refers to user_average_stars = 5; worse eliter refers to user_average_stars = 1: in 2013 refers to year_id = 2013; ratio = Divide(Count(user_id(user_average_stars = 5)),  Count(user_id(user_average_stars = 1)))
SELECT CAST(SUM(CASE WHEN T1.user_average_stars = 1 THEN 1 ELSE 0 END) AS REAL) / COUNT(T2.user_id) , SUM(CASE WHEN T1.user_average_stars = 5 THEN 1 ELSE 0 END) * 1.0 / COUNT(T2.user_id) FROM Users AS T1 INNER JOIN Elite AS T2 ON T1.user_id = T2.user_id WHERE T2.year_id = 2013