Question: What is the percentage of act number 5 in Titus Andronicus?
SQL: SELECT CAST(SUM(IIF(T2.act = 5, 1, 0)) AS REAL) * 100 / COUNT(T2.act) FROM works AS T1 INNER JOIN chapters AS T2 ON T1.id = T2.work_id WHERE T1.Title = 'Titus Andronicus'