source: (gamesradar.com)

Epic Games, Inc. has announced that the Unreal Development Kit (UDK), a free software release that provides uncompromised access to the award-winning Unreal Engine 3 toolset, has exceeded 50,000 users worldwide since its launch on November 5th, 2009. This rapid adoption of Unreal Engine 3 technology extends to approximately 130 countries and 4,500 cities across the globe.