Each license issued under this title shall expire at midnight on December 31 of the period for which it was issued and may be renewed upon application to the Department prior to its expiration. Dealers who have not sold a minimum of 5 vehicles between January 1 and December 31 of each year shall be denied license renewal. The Director of the Division of Motor Vehicles may, on written request by a dealer, permit renewal of a dealer's license for dealers selling less than 5 vehicles for good cause shown in writing to the Department.