The number of user-defined rules by schema and in total

WITH rules AS (SELECT n.nspname AS schemaname,
    c.relname AS tablename,
    r.rulename
   FROM pg_rewrite r
     JOIN pg_class c ON c.oid = r.ev_class
     JOIN pg_namespace n ON n.oid = c.relnamespace
     JOIN pg_authid u ON  n.nspowner = u.oid
WHERE r.rulename <> '_RETURN' AND
(n.nspname = 'public' OR u.rolname <> 'postgres'))
SELECT schemaname, Count(*) AS number_of_rules 
FROM rules
GROUP BY ROLLUP(schemaname)
ORDER BY schemaname;