Model year is represented by the tenth digit. Model years 1981 to 2000 are designated by the letters B through Y, and I, O, Q, U, and Z are excluded. Model years 2001 through 2009 are designated by the letters 1 through 9. The next cycle of the alphabet begins with A in 2010 and continues until 2030. Following that, the 9s will continue until 2039.