What is the percentage of male students in the navy department?
in the navy department refers to organ = 'navy'; percentage refers to DIVIDE(COUNT(name where organ = 'navy'), COUNT(name))
SELECT CAST(COUNT(T2.name) AS REAL) * 100 / COUNT(T1.name) FROM enlist AS T1 LEFT JOIN male AS T2 ON T1.`name` = T2.`name` WHERE T1.organ = 'navy'