instruction: These Are Your Father's Parentheses.
response: SELECT age, COUNT(*) AS programmers, SUM(Reputation) AS total_reputation, SUM(Reputation) / COUNT(*) AS normed_reputation FROM Users WHERE NOT age IS NULL AND age BETWEEN 18 AND 70 AND Users.Id IN (SELECT Users.Id FROM Users, Posts AS answers WHERE answers.PostTypeId = 2 AND Users.Id = answers.OwnerUserId AND YEAR(answers.CreationDate) = 2012) GROUP BY age ORDER BY age