A peak age has been assessed for each position:
The average age for each position has been assessed based on the current age of the 40 best performing players in each position this season from across the English Premier League, French Ligue 1, German Bundesliga, Italian Serie A and Spanish La Liga.
This information comes from whoscored.com, using their average player ratings for players who have played over 15 games in the 2015/16 season.
Where players can play in multiple positions, we’ve only included their primary position as indicated by Who Scored player profiles.
Squads and ages have been sourced from Wikipedia, logging player ages from the date the tournament started. Positions have been used as logged in Wikipedia.