The second big part of the "The European Club Footballing Landscape", from the 2014/2015 season, was about the players.
The average age of first-team squads (in January 2016) can be seen in the following maps below. It seems that the talent-importing leagues tend to have a higher average first team squad compared to talent exporters (such as Netherlands and the Balkan countries).
Russia (27.1) and Turkey (27.1) have the oldest average player age in Europe with the second Dutch league comfortable the youngest (23.1).
The big five have the following average player age: England (26.9), Italy (26.9), Spain (26.9), France (26.0) and Germany (25.4).
The data from around the globe paints the following picture:
The Philippines (27.3), Qatar (27.2) and Mexico (27.1) having the oldest players and New Zealands ASB Premiership (24.1) the youngest top tier outside Europe.
The English Premier League has the highest percentage of expatriate players at almost 70%.
Other countries of the big five were Serie A (55.5%) and Bundesliga (49.2%).
Brazilian players represents ~25% of players in the top tier in Portugal.
Another topic about players is about the recruitment and the market value.
A strong majoriy (25.1 bn or 82%) of global talent (30.6 bn) is concentrated in European leagues with 48% playing in England, Germany, Italy of Spain. Interestingly, this includes five Italian, four German, four English and three Turkish leagues.
And here is the worldwide perspective.
The remaining 5.5 bn from the global talent pool is spread outside Europe. The Brazilian first and second tier, the Argentinian first tier and the first and second Mexican tier holding the greatest value.