How many users became an elite user the same year they joined Yelp?
became an elite user the same year they joined Yelp refers to user_yelping_since_year = year_id
SELECT COUNT(T1.user_id) FROM Users AS T1 INNER JOIN Elite AS T2 ON T1.user_id = T2.user_id WHERE T1.user_yelping_since_year = T2.year_id