What is the ratio of the number of app users that belong to the Securities category to the number of app users that belong to the Finance category?
ratio = DIVIDE(SUM(category = 'Securities'), SUM(category = 'Finance'));
SELECT SUM(IIF(T2.category = 'Securities', 1, 0)) / SUM(IIF(T2.category = 'Finance', 1, 0)) AS per FROM app_labels AS T1 INNER JOIN label_categories AS T2 ON T1.label_id = T2.label_id