How many Olympic events did Michael Phelps II join in total? Find the percentage of the events where he won a gold medal.
DIVIDE(COUNT(event_id where medal_name = 'Gold'), COUNT(event_id)) as percentage where full_name = 'Michael Fred Phelps, II';
SELECT COUNT(T3.event_id) , CAST(COUNT(CASE WHEN T4.id = '1' THEN 1 ELSE NULL END) AS REAL) * 100 / COUNT(T4.id) FROM person AS T1 INNER JOIN games_competitor AS T2 ON T1.id = T2.person_id INNER JOIN competitor_event AS T3 ON T2.id = T3.competitor_id INNER JOIN medal AS T4 ON T3.medal_id = T4.id WHERE T1.full_name = 'Michael Fred Phelps, II'