a little over half of the regular issues, special delivery and airmail stamps issued between the years 1926 and 1952 were produced with intersecting gutters, giving rise to the collection of "centros de hoja". some issues can be quite rare. there were only 200 imperforate sheets issued in 1936 for each of the fourteen stamps issued to celebrate the opening of the free port of matanzas. some of the "writers and artists" series of 1937 sold fewer that 180 sheets. there were only 250 sheets printed of the one peso "death of maceo" stamp in 1948 and the one peso fernando figueredo overprint of 1952. other issues can be plentiful and readily available to collectors.