Question: What is the percentage of the methods' solutions that need to be compiled among the methods whose comments is XML format?
SQL: SELECT CAST(SUM(CASE WHEN T1.WasCompiled = 0 THEN 1 ELSE 0 END) AS REAL) * 100 / COUNT(T2.SolutionId) FROM Solution AS T1 INNER JOIN Method AS T2 ON T1.Id = T2.SolutionId WHERE T2.CommentIsXml = 1