Database: superhero
Question: What is the percentage of blue female superheroes among all female superheroes?
SQL: SELECT CAST(COUNT(CASE WHEN T3.colour = 'Blue' THEN T1.id ELSE NULL END) AS REAL) * 100 / COUNT(T1.id) FROM superhero AS T1 INNER JOIN gender AS T2 ON T1.gender_id = T2.id INNER JOIN colour AS T3 ON T1.skin_colour_id = T3.id WHERE T2.gender = 'Female'