What is the percentage of female athletes below 20s who participated in the 2002 Winter Olympic?
DIVIDE(COUNT(person_id where gender = 'F' and age < 20), COUNT(person_id)) as percentage where games_name = '2002 Winter';
SELECT CAST(COUNT(CASE WHEN T3.gender = 'F' THEN 1 ELSE NULL END) AS REAL) * 100 / COUNT(T2.person_id) FROM games AS T1 INNER JOIN games_competitor AS T2 ON T1.id = T2.games_id INNER JOIN person AS T3 ON T2.person_id = T3.id WHERE T1.games_name = '2002 Winter' AND T2.age < 20