Note: No S, T, U, V, W, X; ignored Y & Z; redirected I, N & P (to H, B & G, respectively)
Grey = No Top-Level '0' Category (A & O)
Legend:
All = Exactly As Is
Some = Specific L3
General = Only Top Level L3 (equivalent to its L2)
Source: https://www.aeaweb.org/jel/guide/jel.php