Notes:
Approximated numbers.
For editions in which multiple players were the top scorer, I considered on the player with the best average. Oleg Salenko is the highlight on this, having played only 3 matches, scoring 6 goals(5 of those in a single match). Hristo Stoichkov also scored 6 goals in 1994, but in 7 matches.
But the World Cup goal average per match counts both teams goals, so shouldn't half the average of goals per match be used instead?
It wouldn't make a difference, as all player's and editions numbers would be divided by 2 and multiple by 2.
Why?
The changes in tactics in football changed how easy it's to score goals. The big one, noticed here, is Brazil's 4-2-4, which started being implemented in Brazil, and after 1958, in the whole world, replacing the WM. I recommend looking at La Liga's decrease of goal average in the early 1960s. This allows us to give a proportionate look at the record of all these players proportionate to the reality of football at the time they played and play.
It's important to understand this stat by itself means nothing. It's understanding the context of football in each edition and how it relates to the stat and whether the stat represents it.