I am sure everyone has thought about it, but just ignored it.
Here is the deal:
(I will focus on Ranked Summoner's Rift)
Games in League of Legends last 20 - 60+ minutes . Still, the stats shown on Ranked Stats include "Per game" averages. An example;
© 2013 Riot Games, Inc. All rights reserved. Riot Games, League of Legends and PvP.net are trademarks, services marks, or registered trademarks of Riot Games, Inc.