If we are talking about countries as much as individuals, then it was Jamaica, Mongolia, Georgia and then Bahrain….
If you want to know why, check out Justine’s blog.
Jamaica won 6 gold medals, 3 silvers and 2 bronze and they have a population of 2.71 million. So, in Jamaica, for every 246,727 people, one won a medal. If the USA had achieved that ratio, then they would have won 10 times as many medals as they did.
However, it is the GDP per person which is particularly telling.
There is apparently a physical reason why Jamaicans are good sprinters though…