SELECT A.table_schema, A.table_name, Count(B.table_name) AS number_of_foreign_keys 
FROM information_schema.tables A
LEFT JOIN 
(SELECT table_schema, table_name
FROM information_schema.table_constraints 
WHERE constraint_type = 'FOREIGN KEY'
) B USING (table_schema, table_name)
INNER JOIN information_schema.schemata C
ON A.table_schema=C.schema_name
WHERE A.table_type='BASE TABLE'
AND (A.table_schema = 'public' OR C.schema_owner<>'postgres')
GROUP BY A.table_schema, A.table_name
ORDER BY Count(B.table_name)  DESC, A.table_schema, A.table_name;