North America's primary risk factors for illness are currently alcohol abuse, malnutrition, obesity, tobacco use, and water sanitation. Obesity is a recent epidemic in North America. The 1990s brought a rise in the average Body Mass Index, or BMI. From the beginning and to the end of the decade, the median percent of adults who were obese rose from 12% to 20%. Alcoholism is the addiction of over-consumption of alcohol and is highly prevalent in the US. There are high incidence rates in many other world regions. Roughly 61% of American adults drank in 2007, and 21% of current drinkers consumed five or more drinks at one point in the last year. There have also been 22,073 alcohol induced deaths in the United States in the past year, about 13,000 of which were related to liver disease. Alcoholism has many risk factors ingrained in North American culture, such as heredity, stress from competition or availability.