Write SQL query to solve given problem: What is the percentage of people who gave the "True North" episode a 1-star rating?. Keep the solution inside sql tag ```sql [SQL-Query] ```
SELECT CAST(SUM(CASE WHEN T2.stars = 1 THEN 1 ELSE 0 END) AS REAL) * 100 / COUNT(T1.episode_id) FROM Episode AS T1 INNER JOIN Vote AS T2 ON T1.episode_id = T2.episode_id WHERE T1.title = 'True North' AND T1.episode_id = 'tt0629477'