Here is a UN list of actual countries and the soldiers they comitted to the Korean war. Note that most came under the jurisdiction of the US and a certain smaller number came under the control of the UN. The URL: http://www.skalman.nu/koreanwar/un-forces.htm
Last modified on 20 December, 2002
The following from: http://combatvets.net/KoreanWar/QA_KoreanW.htm
How many Americans died in the war?
A. There were 33,741 U.S. battle deaths among the U.S. service members serving in the war theater, according to Defense Department figures as of March 15, 2003. Another 2,835 died of non-battle causes, bringing the total dead to 36,576. Another 103,284 were wounded. The figure for all U.N. troops was more than 95,700 killed and more than 200,000 wounded, more than two-thirds of them South Koreans. On the communist side, more than 400,000 Chinese soldiers and nearly 215,000 North Korean soldiers were killed.
Q. What about civilian casualties?
A. About 4-million Koreans, nearly one-tenth of the whole peninsula's population, were killed or wounded, and another 5-million became refugees.
Q. How many U.S. soldiers were taken prisoner?
A. The number of American P.O.W.s was 7,140, of which 4,418 returned, 2,701 died in captivity and 21 chose to remain with their captors.
Q. Was everyone accounted for?
A. More than 8,100 American servicemen were never accounted for. Many of them presumably died in battle and their bodies were never recovered. For others, especially P.O.W.s that never came home, there has been speculation, based on documents later found in the Kremlin archives, that hundreds of U.S. servicemen were secretly held against their will. They were to be used as political pawns by the Chinese or Soviets or to be used for medical experiments, according to a report in Newsweek magazine.