How many kilometers does the average soccer player run per game?

I know in Australian Rules Football's national competition, selected players are wearing GPS units / plotters sewn into the back of their tops so that the coaches can download and review for tactical reasons. The mid-fielders (who do the most running of all of the playing positions) are doing around 20 - 23 kilometers per game (100 minutes playing time, i.e. four 25min quarters). Not much jogging, I'm told; predominantly bet. 50 - 100% max effort or walking (recovery).