Question: Among the employees who wish to receive e-mail promotion from AdventureWorks, how many percent of them are female?
SQL: SELECT CAST(SUM(CASE WHEN T1.Gender = 'F' THEN 1 ELSE 0 END) AS REAL) * 100 / COUNT(T1.BusinessEntityID) FROM Employee AS T1 INNER JOIN Person AS T2 ON T1.BusinessEntityID = T2.BusinessEntityID WHERE T2.EmailPromotion = 1