Write SQL query to solve given problem: How much longer in percentage is the screen time of the most important character in Batman than the least important one?. Keep the solution inside sql tag ```sql [SQL-Query] ```
SELECT (MAX(CAST(SUBSTR(T2.screentime, 3, 2) AS REAL)) - MIN(CAST(SUBSTR(T2.screentime, 3, 2) AS REAL))) * 100 / MIN(CAST(SUBSTR(T2.screentime, 3, 2) AS REAL)) FROM movie AS T1 INNER JOIN characters AS T2 ON T1.MovieID = T2.MovieID WHERE T1.Title = 'Batman'