the "AA" series in Southland and moving progressively north. For some time one could reasonably infer that an "AF" plate hailed from Dunedin, an "AI" plate from South Canterbury, and so on. In some later instances issuers coded plates to the area of registration, such as in 1966 with the allocation of plates beginning with "CE" to the Manawatu-Wanganui region, in 1974–1976 with the allocation of plates beginning with "HB" to the Hawke's Bay region, in May 1989 with the allocation of plates beginning with "OG" to Wellington region, and in July 2000 with the allocation of plates beginning with "ZI" to Auckland region. Motorcycles and tractors These vehicles use one of several five-character systems. Since 2009 the system has consisted of one letter, followed by one number followed by three letters; for example A2ATL. The previous system consisted of one or two numbers followed by three letters. The system incremented the number sequence first, so after plate 12ABC came 13ABC, and 99ABC preceded 1ABD. In July 2009, these plates had reached the "ZUU" range. Caravans and trailers , caravan and trailer number plates have the format nnnLn (e g.123A1). This format was introunced in mid 2021 Before then, these plates had the format nnLnn (e.g. 10A12) launched in 2019. Before then, these plates had the format nLnnn (e.g. 1A123), launched in 2014, prior to that was LnnnL (e.g. A123A), reaching N881S by July 2009. Also, silver-on-black plates can have trailers with motorcycle plates before the "RNA" range in 1990. Two older formats are the Lnnnn format and the nnnnL format which were still shown on black-on-white plates (e.g. 6176M, P8317). Some silver-on-black plates had this format with nnnnI (e.g. 5727I), and some black-on-white plates issued in 2002 have the format (excluding W, Y and Z as the second letter) (e.g. 123AB), in preparation of the new LnnnL format launched later that year. History Before 1925 vehicle registration took place on a regional rather than on a country-wide basis. Vehicles displayed their registration numbers on the right-hand side of the vehicle, often painted on. From 1925, the authorities issued steel plates to vehicle-owners annually. The first plates were United States-made green with white numbers prefixed with NZ (nnn-nnn). The 1926–1927 year was black with white numbers with the following plates black with orange numbers (nnn*nnn). This system changed when steel supplies became limited during World War II: from 1941 plates