What is the percentage of star score 5 that was collected by title "Sex, Pies and Idiot Scrapes"?
percentage = DIVIDE(SUM(stars = 5), COUNT(stars)) as percentage
SELECT CAST(SUM(CASE WHEN T2.stars = 5 THEN 1 ELSE 0 END) AS REAL) * 100 / COUNT(*) FROM Episode AS T1 INNER JOIN Vote AS T2 ON T2.episode_id = T1.episode_id WHERE T1.title = 'Sex, Pies and Idiot Scrapes';