NEARLY half of the world's 1.3 billion smokers live in China, India and Indonesia, the three largest consumers of tobacco products. In China alone, more people smoke than live in the United States. Those countries and others in the developing world represent promising frontiers for the big tobacco companies as they move to win over existing smokers and, according to a new report by the World Health Organization, convince teenagers and women to light up. Smoking has declined slowly in the West. But over the last four decades it has grown steadily in the developing world, in fact, during that time, the respective shares of global cigarette consumption between rich and poor nations flipped:Tobacco products already are responsible for about 5.4 million deaths a year from lung cancer, heart disease and other illnesses, according to the W.H.O., an arm of the United Nations. If trends continue, that number will rise to more than eight million annually by 2030, the agency estimated, with 80 percent of those deaths in the developing world. The eventual toll from tobacco products could be a billion deaths in this centuff, the report said - 10 times the 100 million smoking-related deaths that occurred in the 20th century. The W.H.O. tracked the vigor of tobacco controls worldwide and found them especially weak in poorer nations. One reason is that many governments are in the tobacco business and rely on it for revenue. Case in point: the world's largest cigarette maker is the state-owned China National Tobacco Corporation. BILL MARSH China Has 30 percent of the wodd's smokers. India Has 11 percent of the world's smokers. Indonesia Has 5 percent of the world s smokers Below are percentages of adult smokers in China, India and indonesia - defined by the United Nations as those 15 years and older - and nonsmokers who offer a potentially fucrative market for tobacco products