For cars from 1000000, it was A00000-A99999, B00000-B99999 etc. Possible letters were, in this order, A B D E F G H K L M N P R S T U V Z X Y W. After that, it was 00000A-99999A, 00000D-99999D etc. Possible letters were, in this order, A D E F G H L M N P R S T V W X Y Z; then, the letter was moved to the second position, and then to third (same range as in second position).