Good question. I think that the real number is 20-30,000 (all ethnic groups in comparable numbers) , but the final official number for more "knowledgeable" will be 90-100,000. Serbs will be forced to accept responsibility for 500,000, because this will humiliate them, provide some type of collective lobotomy and will send subliminal intimidating message to other nations.
In 1984 Winston is forced to accept that 2 and 2 is 5 exactly because it is obviously false so his sanity could be broken.
Is most of the responsibility tied to them being accused of starting the wars?.....what percent will they have to accept as "genocide or ethnically cleansing"?
Muslims and to smaller extent Croats are granted official victims status. Serbs are given the villain status (Gypsies are conveniently forgotten).