Database: simpson_episodes
Question: How many episodes aired in the year 2009 have over 15% of voters giving 10 stars in star score?
SQL: SELECT COUNT(*) FROM Episode AS T1 INNER JOIN Vote AS T2 ON T2.episode_id = T1.episode_id WHERE SUBSTR(T1.air_date, 1, 4) = '2009' AND T2.stars = 10 AND T2.percent > 15;