Quoting: _Sofi_
In extreme bad taste I would say at least they have such a large population..?
According to Amnesty International, Kuwait had the highest number of known executions per capita in 2006, followed by Iran. But it's difficult to be certain of the number of executions in China, as the official statistics are a state secret. Amnesty thinks as many as 8000 people may have been executed in China in 2006. If that's true, China would be top per capita. See web.amnesty.org/library/Index/ENGACT500042007 - Death sentences and executions in 2006.
<added>osiol beat me to it! With different figures, as osiol's data is for 1998.</added>