What is the percentage of list created by user who was a subscriber when he created the list?
was a subscriber refers to user_subscriber = 1; percentage refers to DIVIDE(COUNT(user_subscriber = 1),COUNT(list_id))
SELECT CAST(SUM(CASE WHEN user_subscriber = 1 THEN 1 ELSE 0 END) AS REAL) * 100 / COUNT(list_id) FROM lists_users