Database: simpson_episodes
Question: Among the episode that get more than 950 votes, how many of the episodes were nominated for the 'Outstanding Voice-Over Performance Award in 2009'? Find the percentage of the episodes.
SQL: SELECT CAST(SUM(CASE WHEN T1.award = 'Outstanding Voice-Over Performance' THEN 1 ELSE 0 END) AS REAL) * 100 / COUNT(T2.episode_id) FROM Award AS T1 INNER JOIN Episode AS T2 ON T1.episode_id = T2.episode_id WHERE T2.votes > 950 AND T1.year = 2009;