The WHO European Region is the heaviest drinking region in the world, with a prevalence of heavy episodic drinking in over 20% of adults. Alcohol consumption reportedly decreased during the 1990s, then increased and stabilized at a higher level between 2004 and 2006. Consumption varies greatly among countries, with a European average of 9.24 litres of pure alcohol equivalent consumed per person per year. The overall tendency is that consumption has decreased in western Europe and increased in eastern Europe during the last 15 years, although there are huge differences among countries.