Smoking kills more than one in 10 people worldwide.

A recent study in the medical journal Lancet found that, in 2015, 11.5% of global deaths (approximately 6.4 million people) were attributable to smoking worldwide, of which 52.2% took place in four countries: China, India, Russia and the U.S. The study used over 2,818 pieces of research identified through several sources, including the Global Health Data Exchange, World Health Organization, and International Smoking Statistics Database.

Smoking has claimed more than 5 million lives every year since 1990, and its contribution to illness such as cancer, lung and heart disease is growing, especially in lower income countries as the tobacco industry moves to target previously untapped markets, the study found. “The negative effects of smoking extend well beyond individual and population health as billions of dollars in lost productivity and health-care expenditure are related to smoking every year,” it said.

Despite more than half a century of “unequivocal evidence” of the harmful effects of tobacco on health in 2015, one in every four men in the world was a daily smoker. “Prevalence has been, and remains, significantly lower in women — roughly one in every 20 women smoked daily in 2015,” the report found. “Nonetheless, much progress has been accomplished in the past 25 years. The report was funded by the Bill & Melinda Gates Foundation and Bloomberg Philanthropies.

“Smoking remains a leading risk for early death and disability worldwide,” the study found, “and therefore continues to require sustained political commitment.” Smoking was ranked among the five leading mortality risk factors in 109 countries in 2015, rising from 88 countries in 1990, it said. However, only four countries had significant annualized increases in smoking prevalence between 2005 and 2015: Congo and Azerbaijan (for men) and Kuwait and Timor-Leste (for women).

The tobacco industry in the U.S. is heavily regulated. Adding pictures on cigarette packs to illustrate the dangers of smoking increases attempts by smokers to quit, according to a month-long clinical survey released last year and conducted among 1,900 adult smokers, professors at the University of North Carolina, Chapel Hill. The findings were published on the JAMA (Journal of the American Medical Association) Internal Medicine website.

The Family Smoking Prevention and Tobacco Control Act (2009) requires pictorial warnings on cigarette packaging, but the rule hasn’t been enforced. In 2012, the implementation was stalled after the tobacco industry sued the Food and Drug Administration. The U.S. Court of Appeals for the District of Columbia Circuit ruled that same year that the FDA had “not provided a shred of evidence” that the pictorial warnings reduce smoking.

Unlike many European countries, the U.S. tobacco industry, which is worth around $38 billion in revenue and shrinking by 2% annually, does not require cigarettes to be sold in packs without logos. “Over the past five years, the cigarette and tobacco manufacturing industry persevered despite increasingly challenging operating conditions and intense scrutiny from both the government and the public,” according to industry research group IBISWorld.