Firstly rankings were added from September 2003 until now and recalculated each month, from all major Tournaments. It is a League table.
Think of it like Snooker and Tennis there are lots of Tournaments each with there own points. Winning one of the Major ones will give you big points, winning lots of smaller tournaments will also.
I have no doubt that in a few months Amir will rise to the top. But if he is not active, boxers below him will gain points and will pass him. Being Olympic Champion or reaching final at any weight will not guarentee you being number 1 in Europe for four years! Other tournaments will happen and points scored.
Each month as tournaments happen so points will be added. Amirs success at olympics has him high in the rankings, considering this is senior Ranks and he was junior (there are over 100 boxers below him which have all had success at senior level. With out him reaching the Final of Olympics he would not be where he is now.
An example of 2 boxers above Khan!
Domenico Valentino (ITA)
Quarter Final = Olympics
Semi Final = European Championship
Winner = European Union Countries Championship (ESP)
Final = Gee Bee in Helzinki (FIN)
Winner = Military Games In Catania (ITA)
Winner = Algirdas Socicas in Kaunas (LTU)
Murat Khrachev (RUS)
Semi Final = Olympics
Winner = Chowdhry cup” in Baku (AZE)
Winner = Tammer Tournament In Tampere (FIN)
Winner = Copenhagen box cup in Copenhagen (DEN)
Winner = Amber gloves in Kaliningrad (RUS)
Amir Khan (ENG)
Final = Olympics
Winner = Strandja Tournament Plovdiv (BUL)