451-500 units:  1A1
401-450 units:  1A2
351-400 units:  1A3
301-350 units:  1B4
251-300 units:  1B5
201-250 units:  1B6
176-200 units:  2C7
151-175 units:  2C8
101-150 units:  2C9
 76-100 units:  2C10
  61-75 units:  2C11
  51-60 units:  2C12
  41-50 units:  3D13
  31-40 units:  3D14
  21-30 units:  3D15
  16-20 units:  3D16
  11-15 units:  3D17
   1-10 units:  3D18