Depends what kind of sport and what country. 
For example European Championships ; this usually means almost all former Soviet Union, EU/EEZ and Turkey too.
Pool usually is from countries with ~ 823 million inhabiitants.
U.S population is ~ 308 million ( last census ), ~ 323 million ( estimate ).
There's some small for count of inhabitants coutries in some sports for long term were able to be in top 16 in whole European continent.
For some sports there are true powerhouses at world level where their teams maintain to be in top 8, top 12 in world. Get any rank medals and so on is pretty esay there, I think. If they are able to compete with U.S , Russia and Canada at world level. Even get medals and cups.
Some sports in U.S are true powehouse and for them U.S looks like true diamond for many decades.
One example is basketball and NBA. Real powerhouses are even lower level divisions, not only NBA. World's level powerhouses in true top.

For example European Championships ; this usually means almost all former Soviet Union, EU/EEZ and Turkey too.
Pool usually is from countries with ~ 823 million inhabiitants.
U.S population is ~ 308 million ( last census ), ~ 323 million ( estimate ).
There's some small for count of inhabitants coutries in some sports for long term were able to be in top 16 in whole European continent.
For some sports there are true powerhouses at world level where their teams maintain to be in top 8, top 12 in world. Get any rank medals and so on is pretty esay there, I think. If they are able to compete with U.S , Russia and Canada at world level. Even get medals and cups.
Some sports in U.S are true powehouse and for them U.S looks like true diamond for many decades.
One example is basketball and NBA. Real powerhouses are even lower level divisions, not only NBA. World's level powerhouses in true top.