Tobacco consumption imposes costs on both tobacco users and non-users. The costs to nonsmokers clearly include health damage as well as nuisance and irritation from exposure to environmental tobacco smoke. In any given year, smokers' healthcare costs will on average exceed non-smokers'. In addition, tobacco users may impose the financial burdens of their own health problems on others. The World Bank estimates that in high-income countries, smoking-related healthcare accounts for between 6 and 15 percent of all annual health-care costs. In China, where nearly one third of the world's smokers live, a study found that direct medical costs due to smoking accounted for 6 percent of total health-care costs. Another study on China estimated the productivity losses at approximately three times the direct medical costs.