Below is an interesting statistic outlaying the percentage of foreign players in the most prominent leagues across the world. The Barclays Premier League has close to 70% of the players from countries apart from England. The highest amongst all leagues, and a possible marker as to the English league being one of the most popular in the world.
The Italian Serie A has relatively lesser with 55%, while the German Bundesliga has only 46%.
The standout has to be the Spanish La Liga, where only 39% of the players are from countries outside Spain. A true testament to the youth systems and academies in the country, where clubs rely on nurturing home born players more than buying talent.
*Stats as on 7 March, 2014