Who is the person who appeared the most in the series? Calculate in percentage how many times he or she appeared.
who refers to name; appear the most refers to max(count(person_id)); percentage = divide(count(person_id where max(count(person_id))), count(person_id)) * 100%
SELECT T2.person_id, CAST(COUNT(T2.person_id) AS REAL) * 100 / ( SELECT COUNT(T2.person_id) AS num FROM Credit AS T1 INNER JOIN Person AS T2 ON T2.person_id = T1.person_id ) AS per FROM Credit AS T1 INNER JOIN Person AS T2 ON T2.person_id = T1.person_id GROUP BY T2.person_id ORDER BY COUNT(T2.person_id) DESC LIMIT 1