The U.S. state of California first required its residents to register their motor vehicles in 1905. Registrants provided their own license plates for display until 1914, when the state began to issue plates. Plates are currently issued by the California Department of Motor Vehicles. Front and rear plates are required on most types of vehicle in California, including all passenger vehicles. On motorcycles and some other non-passenger types, only rear plates are required. On all vehicle types, registration validation stickers are also required, to be displayed on the rear plate. Since 1947, California license plates have been manufactured by inmates at Folsom State Prison. Passenger baseplates Pre-state plates 1914 to 1962 In 1956, the United States, Canada, and Mexico came to an agreement with the American Association of Motor Vehicle Administrators, the Automobile Manufacturers Association and the National Safety Council that standardized the size for license plates for vehicles (except those for motorcycles) at in height by in width, with standardized mounting holes. The 1955 (dated 1956) issue was the first California license plate that complied with these standards. 1963 to present All plates from 1963 until present are still valid, provided they are displayed on the vehicle to which they were originally issued and the vehicle has been continuously registered. Along with the pre-1963 plates above, these plates can be used for the year-of-manufacture program, with appropriate year sticker. The current 1ABC123 serial format was introduced in 1980. In this format, the ABC123 portion of the serial progresses from AAA000 to ZZZ999, before the leading digit advances by one and the progression begins again. All letters are used, although I, O and Q are only used as the second letter (third digit). Series 1SWD000 through 1TZZ999 and 1WAA000-1YZZ999 have not been issued, while others have been reserved for non-passenger and optional plates, such as 1ZZA through 1ZZZ and 3ZZA through 3ZZG for Livery plates, and 1UAA through 1VZZ for Lake Tahoe, Yosemite and Coastal Protection ("Whale Tail") plates. It is expected that when 9ZZZ999 is reached, the next serial format will be 123ABC1, maintaining the DMV's practice since the 1960s of reversing serial formats at exhaustion. Non-passenger plates Occupational plates On each occupational plate type, the full-size number is constant for each distributing entity, while the small suffix (or prefix on the Special Equipment Dealer/Manufacturer plate) varies. Only rear plates are required for each type. Legislative plates Stickers Optional