count the number of rows in tables

I'd like to fill this table

foo (name varchar(100), rows integer);

with the number of rows for each table that my account has access to.
But EXECUTE with SELECT ... INTO is not yet implemented.
So how do I re-write this function?

create or replace function countrows() RETURNS void AS $$
DECLARE
    rec RECORD;
    nr INTEGER;
BEGIN
    FOR rec IN SELECT tablename FROM pg_tables WHERE tableowner='myaccount'
    LOOP
        EXECUTE 'SELECT count(*) INTO nr FROM '||rec.tablename;
        EXECUTE 'INSERT INTO foo (name,rows) VALUES ('||rec.tablename||','||nr||')';
    END LOOP;
END;
$$ LANGUAGE plpgsql;