List the names of the countries with the below-average number of customers in ascending order of customer numbers.
the names of countries with the below-average number of customers refer to n_name where COUNT(c_name) < DIVIDE(COUNT(c_name)), COUNT(n_name);
SELECT T2.n_name FROM customer AS T1 INNER JOIN nation AS T2 ON T1.c_nationkey = T2.n_nationkey GROUP BY T2.n_name HAVING COUNT(T1.c_name) > ( SELECT COUNT(customer.c_name) / COUNT(DISTINCT nation.n_name) FROM customer INNER JOIN nation ON customer.c_nationkey = nation.n_nationkey ) ORDER BY COUNT(T1.c_name)