Because you chose to apply to a system that limits the total percentage of recipients taken by nationals of any one country? The USA is pretty public with this

Because you chose to apply to a system that limits the total percentage of recipients taken by nationals of any one country? The USA is pretty public with this information along with publishing applications numbers so if it's a process you are interested in understanding or that could impact you personally you had a lot of information to inform you how it all works and what your odds/wait would be?