The average is the average number of games played by a team in a season, so to compute this you need to know the number teams in each year and the number of games each played (which is where is the number of teams in the leage and each team plays each of the others twice, which is true of FA I don't know about the others). The number of teams in each year is not the same so you can't deduce the number of teams from the total number of games and the number of seasons (which is ).

May be you can derive from what is given, but may be not, I have not checked.

CB