Legend (EL_Historical/Elementary_Historical_Boundaries)

04-05 (0) 05-06 (1) 06-07 (2) 07-08 (3) 08-09 (4) 09-10 (5) 10-11 (6) 11-12 (7) 12-13 (8) 13-14 (9) 14-15 (10) 15-16 (11) 16-17 (12) 18-19 (13) 19-20 (14) 20-21 (15)