#4 Serbia
The most surprising inclusion in this list, Serbia is a big fish in Eastern European football. Having a troubled history, Serbia was admitted as an independent nation to the membership of FIFA and UEFA, becoming the sole successor of Yugoslavia and Montenegro, after the dissolution of Yugoslavia.
460 Serbian professional footballers play in foreign leagues, out of which, 91 percent are under contract at clubs in UEFA countries. Most Serbian players migrate to neighboring counties like Bosnia and Herzegovina, Montenegro and Hungary.
The number of footballers playing abroad per capita is one of the best in the world for Serbia, owing to the country's decision to heavily invest in youth programmes. As a consequence, the country's youth team has excelled recently winning UEFA European U-19 Championship 2013 and FIFA U-20 World Cup 2015.