Worldwide, it is estimated that there are about 1100 million smokers, about 1/3 of the global population aged over 15. There are 800 million smokers in developing countries, 700 million of which are men. It is thought that about 47% of men and 12% of women are smokers. Amongst men, the prevalence is similar in developed and developing countries - 42% and 48% respectively, whereas in women the figures are 24% and 7% respectively. This shows the variation in smoking prevalence by WHO region. Prevalence amongst males varies from 30% in the African Region to 60% in the Western Pacific Region. This latter is mostly accounted for by a prevalence of 61% in China. In women, smoking is most common in the European and Americas Regions. Prevalence is very low in women in the other Regions.